THE FLYING SUBMARINE

BY

PERCY F. WESTERMAN

DEAN & SON, LTD.
DEBRETT HOUSE, 41/43, LUDGATE HILL,
LONDON, E.C.4

MADE AND PRINTED IN GREAT BRITAIN

CONTENTS

THE FLYING SUBMARINE

CHAPTER I

SUB-LIEUTENANT HOLMSBY HAS TO INVESTIGATE

"No, no, Wapping. I don't think we need take action. Hang it all, man, what with all these tin-pot scares about foreign spies, we shall be run off our feet."

"But don't you think this is something out of the ordinary?" asked Captain Douglas Wapping, M.V.O., R.N., of his chief.

"Out of the ordinary? Yes, quite—a letter written by a gimcrack hare-brained pensioner, with the evident idea of gaining notoriety prior to calling attention to some grievance real or imaginary. I know their game. Who is this Lieutenant Haslar?"

"I've looked him up in the Navy List, sir. Retired on pension. He was a ranker, promoted for meritorious service in the Bangwan River affair."

"Oh yes, I remember the man. Garrulous as an old washerwoman."

"But he states sufficient in the letter to justify investigation——"

"Well, well, Wapping, have your way then: you always do, somehow or other. Hang it, man, if I had your powers of persuasion I would have received Flag rank long before I did."

That morning Rear-Admiral Pennington had received a letter from an obscure Cornish fishing-hamlet, stating that the writer, Lieutenant Haslar, R.N. (retired), had reason to believe that a mysterious submarine, owned apparently by a foreign power, had been seen cruising in the waters of St. Ives Bay, and that, moreover, a huge airship, that must have its headquarters in the vicinity, was in the habit of making nocturnal passages overland in the direction of Plymouth.

"Send one of the youngsters," continued the Chief Director. "Have you anyone in view?"

"There's Herne, sir, or Bircham, or——"

"How about Holmsby?"

"Well, sir——"

"What?"

"I'm afraid I cannot recommend him."

"Why not?"

"Personally I know little of him, but James has reported unfavourably upon him more than once."

"A fig for James, Wapping. You let that fellow lead you by the nose, as I've told you before."

"You have, sir," admitted Rear-Admiral Pennington's subordinate humbly.

"As a matter of fact, I know something of young Holmsby. A bit high-spirited, perhaps, but after all, is that a failing? Moreover, he came here with an excellent report from the captain of the Tremendous. Send him in to me, and we'll give him his sailing orders."

Accordingly a messenger was dispatched to summon Sub-Lieutenant Reginald Holmsby to report himself in the chief's sanctum, and in a few minutes the young officer was standing as straight as a dart in front of his superiors.

Recently it had been the practice of the Admiralty to appoint junior officers to the Naval Intelligence Department to assist the commanders and marine captains who had hitherto comprised the combatant personnel of this branch at Whitehall. It was purely an experiment, but since these juniors could be entrusted with missions of minor importance, and would gain experience to enable them to tackle more intricate matters, the scheme bid fair to prove a success.

Sub-Lieutenant Reginald Holmsby was a fine active specimen of the British naval officer. Standing five feet eleven inches in his socks, broad yet wiry in body, and with a powerful-looking face that betokened courage and sagacity, he still retained an almost boyish expression in his dark eyes. At sea he had been popular with his messmates, ever ready for a "lark" when ashore,—a propensity that more than once had led him into trouble,—but at the same time he was devoted to his profession and a hard worker. Having passed his Greenwich exams with "firsts" in seamanship, gunnery, and naval law, and "seconds" in torpedo and other subjects, and having qualified for an interpreter in Spanish and Italian, he had been appointed to the Naval Intelligence Department at the comparatively early age of twenty.

"Ah, good-morning, Mr. Holmsby," exclaimed the admiral genially. "I believe you've been on leave for the last twenty-one days. Let me see, you were in Cornwall?"

"Yes, sir."

"What part?"

"The north coast."

"Oh." The Chief Director raised his eyebrows slightly, then: "How did you get there?"

"By motor-cycle, sir," replied the sub., wondering what on earth possessed his superior to evince such an interest in his doings while on leave. Then, with a burst of confidence, he added, "And I had a ripping time, sir."

"I'm glad to hear it," remarked Admiral Pennington brusquely. "Did you happen to come across a place called Pen—Pen (where's that letter, Wapping? Ah, thanks)—Penkerris?"

"Rather, sir. Had a mishap to a sparking-plug and had to wait there until the carrier brought me another from Redruth."

"What sort of place is it?"

"Usual type of Cornish fishing-village, sir. A sort of a kind of a big crack in the cliffs, with a few stone cottages and a little jetty, sheltering perhaps half a dozen drifters or small fishing-craft. When it comes on to blow, you can't go in or you can't get out, because they place huge pieces of timber across the mouth of the basin to check the force of the breakers."

"Hardly the sort of port suitable for a destroyer, for example? Is the harbour tidal?"

"Yes, sir; dries, I should think, at three-quarters ebb."

"Well, Mr. Holmsby, you seem to have gathered a fair amount of information concerning the place, as all officers should do. So what do you say to another visit to this out-of-the-way village? Now read this letter."

Holmsby took the missive and read it through carefully from beginning to end, his face betraying the interest its contents afforded.

"Now this will give you the clue to what you will have to do," continued the Chief Director. "To-day is Wednesday. On Friday you will proceed to Penkerris in the role of a tourist. Contrive to make the acquaintance of this Lieutenant Haslar, and, without letting him know who you are, pump him concerning the cock-and-bull yarn about the foreign submarine and airship. You might also put a few casual questions to the fishermen. By the bye, where is the nearest coastguard station?"

"At Polgwenyth, three miles from Penkerris, sir," replied Reginald promptly.

"Good," exclaimed Pennington approvingly. "Now I leave the matter entirely in your hands. Use your own discretion, and if there should be any truth in this report, communicate with us by wire. If, however, you find that urgent action is necessary, get the aid of the coastguards at Pol—what's its name. Before you start, I'll give you an order to that effect, signed by the officer commanding the division."

"Am I to proceed to Cornwall alone, sir? I venture to suggest that with a companion this business could be carried out more efficiently——"

"How?" interrupted Admiral Pennington, in surprise. "Pray explain."

"Tourists mostly go in pairs, at least," replied Reginald. "Besides, should it be necessary to explore the cliffs, I could dispense with the aid of any of the inhabitants, who would become suspicious as to my intentions."

"I'm afraid, sir, that cannot be managed," interposed Captain Wapping. "We cannot spare anyone else at present."

"I did not mean that," continued the sub-lieutenant quietly. "I've an intimate friend—he holds a civil appointment at the Admiralty—who knows this part of the coast thoroughly. He would be only too glad to come and bear a hand."

"But he cannot be sent officially," replied the Chief Director. "Besides, is he to be trusted to share the secret? It's risky, you know."

"I can rely upon him absolutely," assented Holmsby, with conviction. "However, sir, if you have any objection, I will proceed alone."

"No, no, Mr. Holmsby. You can have a free hand. Now you may go. See me to-morrow afternoon and the necessary papers will be ready for you. In the meanwhile, should anything fresh transpire I'll send for you."

With that Reginald took his leave, but instead of returning to his room he made his way to another part of the huge block of buildings that gives shelter to the numerous and complex departments comprising the Admiralty.

"Is Mr. Tresillian in?" he asked of a uniformed messenger.

"I'll see, sir," replied the man, who recognised his questioner. "I think he's in his room."

In a few moments the messenger returned and requested the sub-lieutenant to follow him.

"Hello, Dick; busy, eh?" asked Reginald breezily, as he was ushered into the presence of his old friend, who was engaged in languidly turning over the dry-as-dust pages of the Home Dockyard Regulations.

Dick Tresillian, a tall, thick-set Cornishman, with so swarthy a complexion that he might easily have passed for a Spaniard, threw the book upon the table and jumped to his feet to greet his visitor. The son of a mine-owner, he had "passed" for Osborne at the same examination as Holmsby, but in the ensuing medical examination a lynx-eyed doctor had discovered that the young Cornish lad possessed a stiff thumb-joint. Placing a small silver coin on the floor, the medico bade the youngster pick it up. Dick's efforts were unavailing, and in consequence he was "ploughed." Thereafter he was wont to bewail the fact that his career was blighted by a threepenny piece. However, he was sent to an engineering college, and in his twentieth year presented himself at the Admiralty for examination—this time for the "civil" post of Assistant Surveyor—and passed with comparative ease.

"Busy?" replied Tresillian. "My dear Reginald, do I look it? Look here, old man, I'm not of a grousing disposition, but honestly I'm sick of this place. Instead of surveying—I haven't set eyes on a theodolite since I joined—I've been sent to supervise a pack of clerks who know more about their work than I ever hope to."

"You've a soft time, at all events," remarked Holmsby.

"That's just what I have to complain about. Instead of using my intellect—and I suppose I have a fair share—I've got to kill time, and help to keep up the utter farce of working overtime for no reason whatever but to swell a rotten 'return.' Honestly, Rex, I don't like it, so I can only hope for a turn at foreign service. But what's up? You look excited."

"I'm off to Cornwall again, old chap."

"Lucky dog; but I thought you had only just returned from leave."

"So I have. This time it's official business. But to get to the point: could you possibly manage to come with me?"

"I wish I could. But what is the reason?"

"Never mind that at present," replied Holmsby, laughing. "But look here: I asked you a question. Can you manage to get off?"

"I haven't had much leave this year. Perhaps the chief might see his way clear to let me off from my arduous duties," said Tresillian, bestowing upon the hateful Regulations a lusty kick.

"Then see him as soon as you can. I'm off to Penkerris the day after to-morrow."

"It's like the call of the blood, Rex. Penkerris is, as you know, within ten miles of my home, and I know every inch of it."

"Couldn't suit me better. Now cut off and see about obtaining leave, and I'll wait here."

"Cannot be done, old fellow," replied the Assistant Surveyor dolefully. "Thanks to red tape, 'twill take a day at least to get the application through."

"Then we must leave it at that," said the sub-lieutenant, who knew full well that his friend's objections were only too well founded. "You'll come if you can manage it. Ten-thirty train from Paddington. Bring your motor-bike, and don't forget this important item: an electric torch. Let me know the moment your leave's approved."

"By Jove, this sounds mysterious."

"I hope for my own sake it is," replied the sub-lieutenant sententiously. "But I'll tell you about it when we are fairly on our way. Now I must be off, for there's much to be done. But remember, not a word as to where we are bound for," and with this parting injunction Reginald Holmsby left his friend to essay the prodigious task of applying for leave.

CHAPTER II

THE OUTRAGE ON THE HIGHWAY

Punctually at a quarter to five on the following Friday afternoon the train bearing Sub-Lieutenant Reginald Holmsby and Dick Tresillian steamed into the terminus at Newquay.

The young Naval Intelligence officer had chosen Newquay as the place from which the motor-cycle journey should commence, since it was within an easy distance of Penkerris, and the arrival of two dust-covered tourists would cause less comment than if they had alighted at the nearest station and jogged leisurely to the scene of their approaching enterprise.

During the run down from Paddington Holmsby had confided to his comrade the object of his mission, and the strict necessity of using the greatest caution.

"We may as well be prepared for eventualities, Dick," he added, and unstrapping a small leather portmanteau, produced a serviceable little revolver.

"Here you are, Dick: carry it in your pocket, so that you can easily get it if required," he continued. "It's a little beauty. Takes .202 cartridges, and will drill a hole through a two-inch deal at fifty yards."

"A neat little weapon," exclaimed Tresillian enthusiastically as he opened the chambers and examined the ends of the six copper cylinders with a critical eye. "But do you think we'll have to fall back upon this?"

"You never know. But you are not jibbing already, are you?"

"Not I," replied Dick stoutly. "Although this is hardly what I expected in an out-of-the-way Cornish fishing-village. But how about you? Haven't you a shooter too?"

"Trust me for that," said Reginald, tapping the breast pocket of his coat. "I've a weapon identical with yours in every respect; so if we are disappointed, we can find some solace in a shooting match along the cliffs. By the bye, is there a decent place where we can put up at Penkerris? You know the place fairly well, I believe."

"When I was there last—that's two years ago—I found comfortable quarters at a Mrs. Pedler's. A homely sort of Cornishwoman, middle-aged, inclined to talk, but strictly honest."

"So much the better," remarked Reginald. "We'll sample Mrs. Pedler's Cornish pasties and cream within a few hours, I hope."

Half an hour after their arrival at Newquay the two comrades were proceeding at a modest twenty knots, as the sub-lieutenant expressed it.

Reginald Holmsby's spirits rose high as he felt himself speeding through the bracing air in the breezy uplands, while his companion was not one whit the less enthusiastic at being once more in his beloved native country. Knowing the route intimately, he led the way with the utmost confidence, pointing out the numerous objects of interest as they sped along.

Presently the road descended abruptly, and the riders found themselves on a wide rolling plain, composed mainly of drifting sand interspersed with patches of coarse grass.

"This is a strange sort of place," remarked Reginald. "I must have missed this district when I came through last month."

"They say the sand is steadily encroaching. It does in several parts of Cornwall. Over there, although you can't see it from the road, lies St. Piran's lost church. It was buried in the sand for centuries, and only discovered a few years ago. However—— Hello! Hang it, Rex, my back tyre's down."

"Hard lines!" ejaculated Holmsby, as he dismounted. "Here, let me bear a hand."

"No need for that," replied Tresillian, who had already turned out his repair outfit. "I'll have it all right within half an hour or so. Look here, if you care to have a look at the church while I'm doing this—it's very interesting—you can walk there and back easily in the time."

"Thanks, but I don't think I fancy a trudge through that desert, on the off-chance of finding the place," replied Holmsby, glancing at the vast expanse of waving grass and soft sand. "I'll stand by and smoke a pipe."

"Please yourself, then," said Dick airily. "But I thought you were a bit of an antiquary."

"So I am, but I don't want to desert you when I might be able to help."

"Well, look here. At the fork-roads, less than a hundred yards away, is an old Roman amphitheatre, called St. Piran's Round. That may interest you, and you can't miss it."

"You seem mighty keen on getting rid of me," remarked Reginald, with a smile. "However, I'll leave you to it, and have a look at the place."

Leisurely following the soft tract at the side of the road, the sub-lieutenant came in sight of a circular earthwork, nearly fifty yards in diameter, a worn gap in the sloping banks enabling him to gain the interior with comparative ease.

Although walking naturally, his feet made no sound upon the soft earth, and on gaining the top of the encircling bank Holmsby found that he was not the only visitor to this relic of bygone days.

Two men were seated on the grass with their backs towards the side on which Reginald was standing. Both were apparently tall and strongly built. Unless he were absolutely certain to the contrary, Holmsby could have been sure that one was his companion, Dick Tresillian, while it did not require much imagination to liken the other man to himself. Both were talking volubly, making rapid and excited gestures, while one of them was coiling away a length of insulated wire.

Struck by the resemblance, Holmsby, out of sheer curiosity, stood looking at the pair, until he became aware, from drifts of conversation that were borne to his ears, that the conversation was being carried on in Spanish.

Instantly the quick-witted young officer reviewed the situation. Here were two men, obviously foreigners, taking counsel with themselves in a secluded spot, while there was no apparent reason why they should be handling electric gear.

"To-night ... will ascend ... strong measures ... Carlos with explosives..."

"This sounds interesting," mused Reginald. "Is it possible that these rascals are the owners or agents of the mysterious airship? It seems to me that this Lieutenant Haslar is not so far out after all."

On first thoughts, the sub. was for slipping quietly away and bringing Dick to the scene of action; but reflecting that the men might observe him as he crossed the gap, and also that much of the conversation might be lost, Holmsby slid softly down the remote side of the bank and listened intently. But though he strained his ears, the rustling of the wind in the grass made the conversation totally inaudible.

"May as well risk it," muttered Reginald, and, regaining his feet, he stood boldly upon the mound.

"After all, if I don't betray any interest in them, they can't do much," he soliloquised. "I've as much right as anyone to be here."

At that moment one of the men took a small cylinder from his pocket and placed it at his side. Holmsby instantly recognised it as a detonator similar to that used in the Service and of high explosive power. As the foreigner did so he caught a glimpse of the intruder standing on the bank above him, and with a muttered exclamation of annoyance he snatched at the cylinder with more haste than discretion and replaced it in his coat pocket. Then both men started to their feet and confronted Reginald with no pleasant expressions on their faces.

The sub-lieutenant now saw that all resemblance to Dick and himself ended, for the man whose back view reminded him of Tresillian, though round-featured and swarthy, wore a short, straggling black beard. The other, equally swarthy, was clean-shaven and inclined to flabbiness.

"What are you here for?" demanded the latter menacingly, in excellent English.

"That's rather a strange question to ask me," Holmsby coolly. "I understand that this place is open to anyone's inspection. Have you any objection?"

Taken aback at the pointed question, the man seemed flabbergasted.

"My friend here is annoyed," said his companion, in a conciliatory tone. "We are touring, and have had trouble with the police for not carrying our driving licences. Moreover, we have had a slight breakdown with our car." And he pointed to the opposite side of the earthwork, although no sign of the car was visible.

"I am sorry to have caused him needless alarm," replied Reginald, though he was perfectly aware of the object of the man's change of front. "As it happens, my friend, who is a skilled mechanic—purely an amateur, by the bye—is a little way down the road; he will be most happy to give you any assistance."

"We shall be much obliged," replied the man, though Holmsby noticed that he gave a deprecatory shrug.

Leaving the two foreigners, the young officer walked across to the road, whence he could see Tresillian struggling with the refractory tyre.

"Dick, ahoy!" he shouted, in stentorian tones. "Here, I want you."

Seeing that Tresillian had heard and was about to join him, Reginald walked back to where the twain were still standing.

"Perhaps, sir, you would like to have a look at our car," said one. "It may be that something is amiss that can easily be rectified without troubling your friend."

"He's on his way now," replied Holmsby. "But I'll see what I can do, if you like."

Without replying, the two men sauntered carelessly round the embankment to where a powerful-looking car stood, bearing a registration plate marked F.O. 445.

"It is this switch that has given us the trouble," said the man who had spoken so abruptly. "See, it is useless," and jumping into the car, he thrust the lever to and fro without any apparent result.

Visions of forcible abduction made Reginald exercise a certain amount of caution, and instead of accepting the implied invitation to board the car, he stood slightly in advance of the off-side front wheel. At all events, Dick would be here soon, and they dared not——

Holmsby's thoughts were rudely interrupted by the car giving a sudden bound. Only by a quick side movement was he able to escape being crushed to death. Then, as the motor gathered speed, Reginald became aware of a rapid succession of reports like the crack of a whip. Instinctively he ducked, his cap falling from his head as he did so; there was a momentary vision of one of the foreigners brandishing an automatic pistol, and with a skid and a bound the car dashed round the corner of the cross-roads.

"What's up, old man?" asked Dick anxiously, as Holmsby rose to his feet, recovered his displaced headgear, and unconcernedly began to brush the dust from his clothing.

"Up? My number very nearly," answered the sub. "They tried to run me down, and finished up by letting rip at me. How I escaped is a marvel. Hello! Why, there is a bullet-hole through my cap."

"Who?" demanded Tresillian.

"How should I know? I can only guess. Dick, old chap, we are on something at last." And Holmsby proceeded to give a detailed account of what had transpired.

"What are you going to do?" asked Tresillian. "Put the county police on their track? There's a station at Perranporth, and in less than half an hour a description of the car will be telephoned to all the police in the duchy."

"Not I," replied Reginald emphatically. "This is our affair, and once we bring in outsiders, the whole business, and the reason for my being here, will become public property. No, Dick; this little incident proves that something mysterious is happening, and I mean to find out what it is. But, by Jove, I believe the brute touched me after all."

Turning up the coat-sleeve of his left arm, Holmsby found that his surmise was correct. A bullet had grazed his forearm sufficiently slight to leave an angry-looking scar.

"Well, that's luck," he ejaculated. "One shot through my cap and another through my sleeve. The beggar with a beard let fly, I should think, ten shots, and it was only the jolt of the car that saved me. There's truth in the old saying that a miss is as good as a mile. But hadn't we better be getting under way? You've finished the repair, I hope?"

"Nearly. I've only to replace the cover and pump up. But ought we not to make a thorough examination of this place? It seems quite possible that, being secluded and sheltered, it might form a landing-place for this mysterious airship on its nocturnal voyages."

"By Jove, I never thought of that, Dick. We'll have a look round."

But a careful search revealed nothing. Beyond a small patch of grass beaten down by the two foreigners as they sat there was no trace of any recent damage done to the "ring." Had an airship alighted, there would bound to be traces of spilt oil and petrol and the marks of the securing grapnels.

"We've drawn blank this time," observed Dick, "So, as you say, we'll proceed."

Hardly had the two comrades left the shelter of the earthwork when a vicious shot of flame burst from above a rough stone wall at less than twenty yards distant, and a shot whistled between their heads.

CHAPTER III

THE MYSTERY DEEPENS

Instinctively both men doubled behind the embankment, their retrograde movement being accelerated by a fusillade of pistol shots; but unscathed they reached a place of safety.

Reginald Holmsby was perfectly cool and collected, while his companion, thanks to his previous training in the Imperial Yeomanry, was no greenhorn, although actually under fire for the first time in his life. Dick could not help experiencing a strange sensation of mingled fear and anger as the bullets whizzed past him, but on taking cover his natural sang-froid reasserted itself.

"You've your revolver, I hope?" asked the sub. noticing that Tresillian was in his shirt-sleeves.

"Rather: I shifted it to my hip-pocket when I began to repair the tyre."

"Good. Now, we can't stop here to be potted at. These fellows will also try to cripple our bikes I'm afraid. Will you edge away to your left and keep them in play, while I work my way round to the right and take 'em on the flank?"

Dick assented, and, revolver in hand, took up the position indicated. So far Holmsby had waited merely to place his cap upon a thorn bush so that it was just visible to the two desperadoes, and immediately set off to carry out his projected flanking tactics.

The appearance of the headgear was the signal for another fusillade from an automatic pistol, and in reply Dick sent three shots in rapid succession towards the spot where a thin bluish haze denoted the presence of their assailants.

Then ensued a long pause, till the sharp report of Holmsby's revolver came from the same side of the stone wall behind which the mysterious foreigners were in hiding.

"After them, Dick, they're off!" shouted the sub-lieutenant, carried away with the fierce joys of victory.

Instantly Tresillian left his cover and ran for the stone wall. Clearing it at a bound, he saw with mixed feelings of delight and regret the forms of the two assailants disappear behind another wall at the far end of the field.

Prudence urged Dick to return to shelter, while Holmsby, having fired two more shots, "just to show there's no ill feeling," as he expressed it, rejoined his comrade. But the precaution, though judicious, was unnecessary, for in a few moments the noise of a car's exhaust was borne faintly to their ears.

"That's settled their hash for the time being, Dick," exclaimed Reginald. "You never gave me a chance, for directly you fired they bolted like hares. I could only get a flying shot at them as they ran. But why should they be so intent on sniping us, I wonder?"

"Goodness only knows," replied Tresillian. "But let's get on the move in case they take it into their heads to have another go at us. Now it comes to the point, Rex, were we justified in firing upon the King's highway?"

"Justified? Gracious, man, do you think I was going to be potted like a pheasant without giving them tit for tat? Mark my words, we haven't seen the last of these gentry."

By this time the two comrades had returned to the abandoned motor-cycles. Dick replaced the cover while Holmsby stood on the alert; but unmolested the repair was completed, and the twain remounted. "Not a word about this affair to anyone, mind," cautioned Reginald, as they descended into the little watering-place of Perranporth. "We may as well make a few inquiries about the car though. We can say that we are looking for our friends in a car with the registration number F.O. 445."

"What does F.O. stand for?" asked Tresillian.

"Can't say off-hand, but here's a garage. Perhaps they have a list of registration letters. I'll ask."

Presently the sub-lieutenant returned with the information that the car was registered in Radnor.

"It's a blind for certain," he added. "However, I'll write off at once to the office and get the chief to make inquiries as to who the owner of F.O. 445 might be. But, honestly, I believe it will be a false clue."

From Perranporth the road led sharply up the side of a steep hill. Even on low gear the cycles made hard work of it, but wild scenery amply compensated the drivers.

Away on the right, betwixt rugged cliffs that formed vast defiles, could be seen the blue waters of the Atlantic, now tinged with a deep crimson by the setting sun. To the left a chain of rugged hills, fringed by an irregular line of tall chimneys, met the skyline, while ahead, the gorse and bracken covered downs; capped here and there by the "stack" of a gaunt deserted mine, rose in seemingly endless persistence.

"Think we'll take that without trouble?" asked Reginald, pointing to a conical-shaped hill that reared itself to a height of nearly seven hundred feet, the white road showing clearly as it ascended a spur of the formidable beacon.

"We don't want to," replied Dick. "The road to Penkerris branches off just here. You must have missed the hill as well when you came in from St. Ives."

"Yes, you're right," agreed Holmsby. "I struck inland to avoid it. But I remember this lane well."

They had now reached the by-road, which, assuming a loose rough surface, plunged steeply down a narrow rocky valley. Ahead, the power-house and gaunt chimney of a still working copper mine stood out clearly against the evening sky.

To the left of the road ran a swift stream, not of sparkling water like the brooks of Devon, but of a bright crimson hue, being fouled by the mundic from a score of copper mines.

The line terminated abruptly almost at the edge of the sea, where a stretch of slate-coloured pebbles did duty for the beach. On either hand the cliffs rose sheer to a height of over a hundred feet. To the right as far as the eye could reach the cliffs continued in a succession of bold bays, while in the other direction a frowning granite headland restricted the landscape to a distance of less than a quarter of a mile.

At the base of this cliff two massive stone jetties enclosed a small artificial harbour, the only visible means of access from the shore being a series of steps cut into the solid rock and protected by a rough handrail, while a wooden crane afforded the means of removing the scanty catches of fish or the cargoes of the colliers and other coasters that at rare intervals put into the basin.

A few stone houses, perched on every available portion of level or slightly sloping ground, comprised the hamlet of Penkerris. Picturesque from all points of view, it would have been a popular artists' haunt and watering-place but for the presence of the mineral-charged stream. Discolouring the sea for a space of a hundred yards from the diminutive beach, it rendered Penkerris impossible for bathing. Doomed to stagnation, the hamlet was left severely alone by holiday-makers, and was fifty years behind the times even as far as the rest of the duchy was concerned.

"Here's Mrs. Pedler's cottage," said Dick, pointing to a rambling two-storeyed cottage, the granite walls of which were nearly hidden by a profusion of creepers. "No doubt she can accommodate us; if not, I'm afraid we're done, for there's not even an inn nearer than St. Agnes."

Leaving their motor-cycles outside the garden gate the two comrades, in the now fast-gathering twilight, made their way up the irregular path and knocked at the door.

It was opened by a portly dame, who peered at the two mackintoshed-clad figures over the rims of her glasses.

"Good-evening, Mrs. Pedler," exclaimed Dick genially.

"Good-evening, sir, whoever you might be, for I can't a-bring you to mind. Ah, to be sure, 'tis Mr. Tresillian. Come in, sir, and be kindly welcome."

Within ten minutes the two comrades were doing justice to a plentiful Cornish supper, while their hostess was bustling to and fro with an almost too attentive solicitude as to their wants.

"By the bye, Mrs. Pedler, how is Sampson's Cove looking? Last time I was here it was about to be sold."

"Don't mention it, sir," exclaimed the old dame raising her hands in dismay. "A gentleman from Lunnon 'as bought it and a rare slice of the down as well. He be a real stranger gentleman, sure, though I can't call to mind that I ever set eyes on him. But people in the village who knows says he's in league with the Evil One."

"A kind of limited liability company, eh?"

"I can't say as I knows what that is, sir, but 'tis a real bad company whatever he keeps. What goes in there goodness only knows, for they've put a girt iron fence all around, and no one in the village 'as ever set foot inside since for nigh a twelve-month."

"Then we shan't be able to visit the cove as I used to do?"

"No, sir, that you can't. It's fair cruel to stop up the path to the cove like that. Mr. Haslar up at Anchor Cottage is right vexed about it. But that ain't the worst. The Lunnon gentleman isn't satisfied with tearing all over the place in a motor, but he's often flying through the air in a girt thing that makes an awful noise."

"What's that, Mrs. Pedler?" asked Holmsby, who had hitherto been patiently enduring the old lady's conversation. "Travelling through the air? Is that a fact?"

"As sure as I'm alive, sir; for, though I'd told you I'd never set eyes on him, his flying-machine well-nigh scared the wits out of I."

"Oh, what sort of machine is it—an aeroplane?"

"Oh no, sir," continued Mrs. Pedler, "'Twern't that; 'twas more like the size of my poor dear husband's ship, and she was a brig of 200 tons register," and the old lady pointed to a gaudy oil-painting of a trader that occupied a prominent position on the wall.

"'Twas like this," Mrs. Pedler was now in full swing, and needed no prompting. "Last June, it being my sister's wedding-day so I am sure of the date, I had been over to Redruth to spend the day. Sure as fate I mussed my train, and it was dark when I caught the next. As you know, sir, it's a pretty goodish step from St. Ann's Road station to here. Just as I were a-coming to the cross-roads I heard a most uncommon sort of floppin' in the air, and this girt flying thing comes right over my head. I were turble skeard, an' took to my heels an' ran—an' me with rheumatics in my knees an' all."

"What happened then?" asked Reginald.

"I came straight home. Next mornin' I told the police sergeant, but he actually told me—a respectable widow—that I had been having a drop too much. 'Twas the same with everybody I told, except Mr. Haslar; but now I knows they knows I was not telling fancy tales."

At length, from sheer want of breath, Mrs. Pedler stopped and left the two comrades alone. Supper over, Holmsby suggested a stroll before turning in. "The moon will be up by now," he remarked. "And a saunter as far as the headland will do us no harm. I'm afraid, though, we will not see anything of the nocturnal airship, unless we make a night of it; and, candidly, I've had enough excitement to last me for the present."

Accordingly, the twain took the left-hand or north-western cliff path, and in about a quarter of an hour reached the extreme point that separates Penkerris Bay from its neighbour.

Everything was calm and peaceful. Beyond the glimmer of a few lamps in the hamlet and the regular flashes of Godrevy Light almost on the horizon, extreme darkness brooded over sea and land, for the moon was obscured behind a bank of clouds.

"Quiet, isn't it?" remarked Holmsby, puffing contentedly at his pipe.

"Simply grand," replied Tresillian. "But we've come in the wrong direction to see anything of Sampson's Cove."

"I meant to," said the young officer. "To-morrow we'll have a quiet day and find some excuse to keep watch all night. So——"

"What's that?" exclaimed Dick hurriedly, pointing to a faint luminosity on the water several hundred feet below the spot on which they were standing.

Following the direction indicated Holmsby saw a phosphorescent swirl disturbing the tranquil water close to the edge of the next headland. After watching it for some moments the sub. rose to his feet.

"Let's get back," he remarked. "You're getting jumpy, Dick. It's only a shoal of mackerel."

"I've never seen a shoal like that," maintained Tresillian stoutly. "Hold hard a minute."

The luminous patch, whatever it was, was slowly moving seaward, yet it retained its apparently compact form.

Just then the moon shone forth through a rift in the clouds, flooding the sea with its silvery light, and the illusion vanished.

"Come along, Dick," repeated Holmsby. "You have caught a bad nervous disorder."

But Tresillian obstinately refused to budge, keeping his eyes fixed upon the spot where he had last caught a glimpse of the mysterious swirl. For full five minutes he remained thus, while Holmsby, with ill-concealed impatience, sat down upon a piece of rock and refilled his pipe.

Just as Reginald was in the act of lighting up, a sudden exclamation from his companion caused him to throw down the match and spring to his feet. Half-blinded by the glare of the match, he could see nothing, but he distinctly heard the faint whirr of a powerful motor.

As for Tresillian he gazed in astonishment at what he saw, for apparently from the depths of the sea a dark grey cylinder had emerged, and with incredible swiftness rose in the air to an immense height, speeding rapidly in a south-easterly direction.

By the time Holmsby had accustomed himself to the darkness once more, the mysterious airship was out of sight and hearing.

CHAPTER IV

CHECKMATE

"What do you think of it?" asked Dick. Being a born diplomat, he had prudently refrained from the irritating exclamation, "Wasn't I right after all?" but he could not help feeling inwardly elated at his discovery.

"Didn't see it at all," replied Holmsby, scorning to beat about the bush. "I was lighting my pipe and the glare of the match put me out of the running. What was the thing like?"

"As far as I could see, it was similar in shape to our airships, only smaller. Whatever it was it shot up from beneath the sea, floated for a brief interval, and then ascended."

"Are you sure it came from below the surface? I can understand an airship starting from a floating position on the water, but the very idea of an object possessing the extreme buoyancy to lift in the air and sufficient weight to sink in the water seems utterly opposed to every law of nature and science."

"I'm practically certain the thing did shoot up from beneath the surface."

"Then, Dick, we are on the track of an invention that will revolutionise warfare—a submarine possessing some powerful and hitherto unknown agency to make it able to resist an enormous pressure of water and also to enable it to raise itself in the air. A truly formidable tool in the hands of an unscrupulous inventor. But it's not of much use waiting for further developments to-night. To-morrow we'll pump old Haslar, and in the evening we must take steps to fathom the mystery."

That night Dick Tresillian could not sleep. The events of the day had excited his feelings to such an extent that for hours he lay uneasily in his bed listening with feelings of envy and irritation to his companion's deep, regular breathing.

At length, finding slumber impossible, Dick rose and went to the open window, where he remained lost in thought, yet hoping to detect the sound of the returning airship, till the dawn began to disperse die shades of night.

Then dead-beat he threw himself upon the bed and slept, seemingly but a few minutes, until he was roused by Holmsby's voice demanding whether he meant to spend the day in bed.

"What's the matter with you, by Jove?" asked the sub., noting his companion's tired expression. "You look as if you hadn't had a wink of sleep all night."

"Neither have I—I simply couldn't. But I don't think we'll witness the departure of the airship to-night."

"Why?"

"I was looking out of the window until dawn, and I can swear I never heard a sound. So perhaps she's off for good."

"I trust not. But get your things on and we'll go for a swim. There's nothing like salt water to freshen you up."

On the way down to the little harbour they met a fisherman returning from his night's work. The man greeted them civilly enough, but both remarked that he eyed them with a certain amount of suspicion.

"Perhaps he takes us for some of the new owners of Sampson's Cove," said Dick. "If so, that's awkward. We must disarm suspicion in some way."

"Mrs. Pedler will enlighten them on that subject, never fear," replied Reginald. "But here we are, and there's another boat coming in. If we can hire it for an hour we can have a decent swim without running the risk of being dyed a bright red."

Descending the steep flight of steps, the two men reached the jetty. Without hesitation the fisherman agreed to take them off, for his luck had been out, and less than half a dozen small whiting had been the reward of a night's hard toil.

"Can you run us round to that cove I see yonder?" asked Holmsby, pointing to the mysterious Sampson's Cove. "The water seems clear enough there."

"No, I won't," replied the fisherman bluntly, resting on his oars. "You be strangers here?"

"Staying at Mrs. Pedler's. But I remember you," said Dick. "You took me out fishing when I was here two years ago."

"Now you comes to mention it, I did, sir," replied the man. "But you ain't anything to do with they up there—are you, sir?" and he jerked his head in the direction of Sampson's Down.

"No, we're not," assented Tresillian. "But what's the matter that you should refuse to take us to the cove?"

"Can't do it, sir. The place has been sold, and a pretty fine sort o' chap 'as bought it. I believe he's a luney, for he's fenced the place right in and don't allow a single soul in Penkerris to set foot inside. If a boat sets her keel in the cove a lump of rock'll be sent flying from the cliff—an' who's to prove it ain't pure accident?"

"Sounds lively," commented Dick.

"What sort of man is the owner of Sampson's?" asked Reginald. "Tall? Does he use a motor-car?"

"No, he's a little 'un. Leastways, I think so, but I only just caught sight of'n once. Ne'er a blessed moty-car 'ave I seed, either."

"Surely he must get provisions from somewhere?"

"Not in Penkerris nor in St. Agnes. An' 'tis said that he only lives in a little house over t'hill. Sure he's a real wrong 'un. There's been nought but bad luck in the fishin' since he comed here."

"How's that?" demanded Holmsby sharply.

"Don't know," replied the fisherman with equal brevity, mistaking the tone of his questioner. "But 'ere you are, sir; no tide fit to speak of and puffectly safe for swimmin'."

"You frightened the old chap," observed Dick on their return to the village. "He shut up like an oyster."

"Yes, I noticed that. 'Twas an unfortunate blunder on my part. However, we'll have some breakfast, then cross-examine old Haslar."

Anchor Cottage was the highest-situated building in Penkerris, standing within fifty feet of the edge of the low cliff on the north-eastern side of the beach. It was a two-storeyed stone building with a roof of thick slate slabs. On two sides there was a well-stocked flower-garden, while seaward a small lawn, with a flagstaff in the centre and half a boat that had been converted into a look-out perched perilously near the brink of the sheer cliff.

Half hidden in the profusion of flowers was a short, stocky, red-faced man with a neatly-trimmed iron-grey moustache and torpedo beard. In his navy-blue reefer coat there was no possibility of taking the individual for anything but a retired Service man.

"Can we reach the cliff by this path?" asked Holmsby by way of opening a conversation.

"You may, sir, though this is private property. This way. I'm afraid you can't go very far because of the fence."

"Thanks awfully," replied Reginald, purposely ignoring the latter part of Lieutenant Haslar's reply. "You've a fine display in your garden, if I may be allowed to say so."

"Not bad," replied the retired officer modestly.

"I suppose you've had a lifelong experience of gardening. These rows are worth exhibiting."

"Never touched a hoe as far as I remember until twelve years ago. I'm a Service man."

"A Service man?" Holmsby was the perfection of innocent ignorance.

"Yes, sir, a Service man. Pensioned carpenter-lieutenant from the Royal Navy. Haslar, John Haslar is my name, and I'm not ashamed to answer to it."

"Well, Mr. Haslar, we must thank you again for your courtesy—but what was that you said about a fence?"

The old man's face clouded.

"Yes, that blamed fence you can see over there. Turns Sampson's Down, with one of the finest, if not the finest, outlook on the coast into a private arsenal or something worse."

"A private arsenal?"

"Ay, 'tis about time the Government took steps in the matter. They aren't so particular as when I was in the Service, or they would have sent a detachment of coastguards to investigate. Instead of that the 'gobbles' have nothing better to do than to plant cabbages. It's an outrage, sir."

"I'm afraid I can't follow you."

"Well, I know for certain that the fellow who has bought Sampson's Down and the cove is nothing less than a foreign spy, if not worse. Night after night I've seen one of those airships start off from the cove. What for? Why, Plymouth isn't more'n two hours' run, so you can draw your own conclusions. I've written to the Admiralty about it, but beyond the usual acknowledgment they have taken no action."

"I've heard tales in the village about an airship. What sort of craft is she? Where is she kept when not in use?"

"That's where I'm beat, sir; never been able to make out. But might I ask why you take such an interest in the thing?"

"It is your account that interests us, Mr. Haslar. You see we are visitors here, and never expected to hear strange tales about an airship in this out-of-the-way Cornish hamlet. By the bye, would you care to have a drink? There's a 'pub.' in the village, I believe?"

"The sun's not over the foreyard yet, sir."

"Very good," replied the sub-lieutenant, but the next instant he was biting his lip in his mortification: by his tacit acceptance of the pensioner's refusal he had given himself away.

"You are a Service man yourself!" exclaimed Haslar, looking Holmsby straight in the face.

"I am," admitted Reginald. "And what is more, I've been sent down expressly by the Admiralty to investigate the facts contained in your report."

"Then why the deuce didn't you say so, instead of beating about the bush? Confound it, you cocksure youngsters want to pick the brains of a man old enough to be your grandfather and take all the credit. I'll be hanged if I tell you another thing."

And turning on his heel the irate lieutenant walked off, leaving Reginald and his companion standing dumbfounded in the garden.

"I've made a mess of it again, by Jove," ejaculated the former, when he had recovered his tongue. "That's twice this morning already."

"Never mind; the old chap will open out next time we fall across him," said Dick. "But at any rate our investigations are checkmated in this direction, so we may as well start on another tack."

Armed with a pair of powerful prism-glasses, the two investigators hired a boat, and dropping anchor about a quarter of a mile from Sampson's Cove, began ostensibly to fish.

Under the shelter of the loosely furled sail they took turns to scan the frowning cliff. But although they persevered till late in the afternoon, not a single human being nor any sign of animation could be discerned.

"Evidently the place is deserted," remarked Holmsby. "The airship has either left for good or she has gone for a prolonged cruise. However, we'll renew our researches after sunset."

CHAPTER V

THE SECOND NIGHT

"Any luck, sir?" asked the boatman, as the two pseudo-fishermen returned to Penkerris Harbour.

"Not a single bite," replied Dick. "But we're going to try again to-night—I believe night is the best time for this sort of game."

The man looked at them with a marked shade of suspicion, but after all he was well paid for the hire of his boat, so what did it matter?

"It used to be a good place for night fishing, sir," he said. "Perhaps with a bit o' luck you might pick up a few bass or whiting."

"We can but try, so will you please see that the boat is ready and the bait on board by half-past eight."

"You won't be runnin' no risks wi' my boat, will 'e, sir? You see she's all I got to keep me going."

"I'll try not to," replied Holmsby. "By the bye, what is she worth?"

"A matter o' ten pun', seein' as she ain't no chicken," replied the man honestly.

"Well, I'll tell you what I'll do, Come with us to our diggings and I'll hand Mrs. Pedler a ten-pound note to give to you if the boat's lost—which I don't expect for a moment will be the case."

"Very good, sir," assented the man, with an air of relief. "I knew'd as you were a gentleman."

"We're making everyone in the place suspicious," remarked Dick, after the boatman had left the cottage. "There's old Haslar fairly up the pole: I wonder if he's been giving the show away?"

"I don't mind particularly if the villagers are suspicious," asserted Reginald, "so long as we can achieve our aim; and I mean to do it—outside influences won't affect the case. Now the best thing we can do is to have a nap after dinner till eight o'clock so that we can be fit for our night's work."

The evening was warm and balmy; not a ripple disturbed the surface of the sea, even the usual ground-swell failing to assert itself. Quite three miles to seaward a Rochester barge, a Padstow brig, and a large barquentine were drifting idly with the flood-tide. Almost hull down, two tramps were ploughing Bristolwards, each sending up a thick column of smoke, while far away in the direction of Trevose Head the sea was dotted with the brown sails of the Padstow fishing-smacks.

"We shall only have ourselves for company," remarked Holmsby, as they surveyed the deserted sea in the vicinity of the rock-bound coast. "Even the fishing-boats seem to give this part a wide berth. You've your revolver handy, I hope?"

"Trust me for that, after our meeting with those rascals at St. Piran's Round," replied Dick. "But here we are, and the boat's ready."

It was now barely quarter flood, and the truck of the boat's mizzenmast projected only two feet above the edge of the jetty. On the fore side of her mizzen, as is usual with the fishing-craft of these parts, a square iron frame with glass sides contained an oil lamp. This the considerate boatman had already lighted.

"Good-evenin', gentlemen. Everything's ready. I'll bring her round to the steps."

"No, don't trouble," said Reginald. "We'll slide down the shrouds. Now, Dick, inboard with you."

This Tresillian accomplished, but to his surprise Holmsby, in following him, awkwardly collided with the lamp, his shoulder demolishing two panes of the glass.

"Steady, cap'n," exclaimed the boatman reproachfully, as he witnessed the destruction of his property.

"I'm sorry," said Reginald. "However, I'll make good the damage."

"And you'll be wanting another lamp? I'll run and get one."

"No, we won't take another. Besides, the moon will be up in a couple of hours."

"Not before eleven-thirty, sir."

"We'll do without a light," said Holmsby decisively.

Owing to the flat calm it was useless to hoist sail, so using their oars with a will the two comrades urged the boat through the entrance to the little harbour and gained the open sea. That they were the object of much local curiosity was evident from the fact that on a seat perched on the edge of the lofty cliff that bounded the landward side of the harbour half a dozen fishermen were watching them through telescopes and binoculars.

"Don't raise your voice above a whisper," continued Reginald. "On a fine night like this sound travels so clearly that these fellows could hear us talk when we are a quarter of a mile away. I managed that lamp very nicely, didn't I?"

"I didn't think a sailor would be so confoundedly clumsy," was Dick's remark.

"Nor is he. I smashed it on purpose; otherwise, we would have had to keep it burning."

"Why? Surely we could have extinguished it if we wanted to?"

"If we had there is a great possibility that the fishermen ashore seeing the light go out would think something was amiss and would put off to us. Now we can lie fairly safe from observation, for from a great height a small craft like this would be almost invisible even in the moonlight."

It was a weary vigil. Though both men kept their eyes glued to their night-glasses in turns and scanned the horizon and the rugged outlines of Sampson's Down, their efforts seemed fated to be unrewarded.

Hour after hour went by. The moon rose and ascended high into the sky, throwing the bold headland into strong relief; but still no signs of the object of the night's watch.

Suddenly at about two in the morning the anchor-warp trembled violently. The boat's nose dipped to within a few inches of the water and gathering way the little craft began to shoot rapidly ahead.

"Stand by!" shouted Reginald warningly to his comrade, and grasping his knife he made his way for'ard, lying full length upon the diminutive half-deck.

Dick, hardly able to realise the situation, "stood by" very effectively by sitting on the bottom boards and gripped the thwart with both hands. He was aware that the little craft was being drawn towards the cliff at no mean speed, while a sullen agitation of the sea showed that there was some large moving body travelling beneath the surface.

Then, without warning the boat's bow dipped once more till the water swirled over the half-deck. Holmsby, his arms and shoulders immersed, slashed at the anchor-rope, and the next instant, the boat, released from the downward pressure, bolted up like a cork, well-nigh throwing the sub. from his precarious perch.

"I thought we should have to swim for it," he exclaimed. "And we've lost our anchor."

"What has happened?" asked Dick, still remaining in his undignified position.

"Oh, nothing: only the submarine airship come home."

"What to be done now?"

"Done? Why wait. The fun is only just beginning. The tide's slack and with no wind the boat won't drift very far. Get the oars out, though; we're a bit too close in."

"By Jove, we are!" exclaimed Tresillian, as he noticed for the first time that they had been dragged or towed almost between the two horns of Sampson's Cove.

"There's one thing I've discovered. There's a submarine passage underneath the cove, and that's where the craft has gone. If I hadn't cut the rope we would have been carried down with her, and the suction would certainly have drawn us through the tunnel. Now, that's far enough: lay on your oars and watch."

For more than another hour they waited, giving an occasional stroke with the oars to counteract the tide.

Presently Reginald touched his companion lightly on the shoulder.

"Look!" he whispered.

Standing on the summit of the cliff, his outline silhouetted against the pale dawn, was a man. For a few moments he looked in the direction of the boat, then, seemingly without the faintest hesitation, as the head and shoulders of another person appeared above a slight rise in the sloping ground of the down, the foremost man sprang into space.

Dick gave an involuntary gasp, that trailed off into an exclamation of astonishment, for the falling man's descent was gradually retarded, till it looked as if he were descending a flight of stairs. Once or twice he appeared to be drawn towards the face of the cliff, but by a movement of his arms he thrust himself clear, till he disappeared from view behind a mass of boulders fronting the base of the headland.

Then the second followed, descending in almost the same manner.

Holmsby glanced at his companion.

"What do you make of it?" he asked. "They must have descended by a rope or steel wire, but I can't make one out: can you?"

"I'm pretty certain there's no rope: but how did they manage it?"

Dick was positively shivering, while in spite of his iron nerve Reginald felt a cold chill in his spine. There was something decidedly uncanny in the manner in which the two men literally threw themselves over the towering precipice and were prevented by some invisible agency from being dashed to pieces.

"They spotted us," continued Holmsby.

"Do you think so? We're still in the gloom," said Tresillian. "But, honestly, old man, I feel creepy."

"So do I," admitted Holmsby frankly. "Still we're here, and I mean to remain till sunrise."

But though they resumed their vigil till the sun tinged the eastern sky no further developments were forthcoming.

"Let's get back," said Reginald. "I've seen as much or more than I expected, but still I'm not satisfied. To-night I mean to scale the fence and explore the top of the cliff. Are you game?"

"Yes," replied Dick.

CHAPTER VI

THE THIRD NIGHT

The following afternoon Reginald and his companion walked into St. Agnes, where a telegram was awaiting them:

"F.O. 445 motor-cycle owned by Scatterthwaite, Methodist preacher Presteign."

"That's a false scent laid bare," commented Holmsby. "The number of the motor-car is obviously a blind, so it would have been no use to have attempted to track it by its identification plate. I shouldn't wonder if the rogues kept a stock of them. However, there is some consolation that we need not worry about what is obviously an attempt to lead us astray. Had we done so we might have complications with an irreproachable Radnor parson."

"By the bye, we may as well have a newspaper," remarked Tresillian ere they left the shop. "I haven't seen one since we left town, and it's strange how you miss being in touch with the rest of the world."

"Here you are—read this," he continued, after scanning the pages of a county paper.

Holmsby took the limp pages and read:

"Plymouth—Monday.—An airship passed over the town in the early hours of Sunday night. After hovering above the Citadel it headed towards Devonport Dockyard, where it descended to within two hundred feet of the ground. When last seen it was proceeding rapidly in the direction of Tavistock. Much uneasiness has been caused in official circles by its visit, since it is well known that none of the airships attached to the Port have left their sheds during the week, while the movements of Service Aircraft in other parts of the kingdom have been fully accounted for."

"That's let the cat out of the bag," growled Holmsby. "Once the papers get hold of the news our people will be spurred on to immediate action. We must look sharp or the chief will be sending a senior to investigate."

During the remainder of the walk back to Penkerris conversation was dropped. Both men were thinking deeply.

"Look here, Dick," said the sub-lieutenant at length. "I didn't want to report to headquarters until I had unravelled the mystery—since the chief treated the matter lightly. But now, for our own credit, I will draft out a full report of our investigations to date and give particulars of our impending expedition. This will satisfy the old man, and perhaps stop him from sending Boldrewood or any of the senior fellows down."

Holmsby acted accordingly, and having posted the missive and partaken of supper, the two investigators prepared for their nocturnal expedition.

"I've commandeered one of Mrs. Pedler's footstools," remarked Reginald. "It will easily stow into this bag, and my electric lamp too. By the bye, you might run down to the harbour and get Trevaskis to lend you a coil of rope—twenty-five fathoms of inch-and-a-half stuff if he's got it."

In less than a quarter of an hour Dick returned with more than the required length slung in coils over his shoulder.

It was now dark. Dividing their burdens the two adventurers left the village and began the steep ascent that lay betwixt them and Sampson's Down. Here they rested ere descending the intervening valley.

"Stand by; there's some one coming this way," whispered Holmsby.

For want of better shelter the twain flung themselves on the grass, while the short quick gasps of a person obviously out of breath came nearer and nearer.

Presently a short, thick-set figure passed within five yards of their place of concealment, and ignorant of the presence of Reginald and his companion, breasted the crest of the hill and descended towards the hamlet.

"It's old Haslar. I wonder what he's doing out here at this time of night?" whispered Holmsby, as the lieutenant's outlines were lost to sight in the darkness.

"Doing? Why, trying to cut us out," replied Dick, as they shouldered their loads. "I hope he hasn't raised the alarm."

Another quarter of an hour's brisk walk ending with a stiff climb brought them to the fence. It was a formidable affair, being of the so-called "unclimbable" variety, and consisted of double-barbed rails seven feet in height with intervening spikes of about two-thirds the length of the taller ones.

Without a word Reginald wedged the footstool upon two of the sharp prongs; then bending down he signed to Dick to jump on his shoulders. The next instant Tresillian was seated upon the precarious perch, whence he slid softly to the ground.

"Hand over the gear," he whispered.

Holmsby passed the sack containing the lamp, but instead of throwing the coil of rope to his companion he placed the bight of the coils between two of the spikes. Then gripping the upright and inserting his foot into the lowermost portion of the coil of rope, Reginald swung himself easily upon the stool, thence rejoining his comrade.

They were safely within the fence, but how were they going to get out again should they meet with opposition?

From this point the cliff path continued, though grass-grown through disuse. In places it passed perilously close to the edge of the cliff which in many places had recently crumbled away.

"Steady a moment while I hitch the end of the rope round my waist," whispered Holmsby. "You hang on to the rest of the coil and walk a few yards behind me."

Presently they came to the spot immediately over the head of the cove and where the mysterious descent of the two men had occurred. As Reginald had expected, there was no sign of a windlass or any mechanical means by which a descent could be made, but instead they found a well-defined path leading up the gently-rising ground above the cliff.

"This way," said the sub, in a low voice. "We're on the track."

Before he had gone fifty yards Holmsby stopped short at the brink of a yawning shaft barely twenty feet in diameter. It had been at one time enclosed by a low stone wall, but nearly half of the stonework had been levelled.

"Stay where you are and keep the rope taut," he cautioned. "I'm going to lean well over this pit."

For nearly five minutes Holmsby listened. To his great satisfaction, he distinguished the rhythmical purr of machinery deep in the bowels of the earth, while at regular intervals came the dull swish of the ground-swell.

"This funnel communicates with the sea," he whispered, as he rejoined his comrade. "I fully expected it did. Now I'm going to attempt the descent. If this is the shaft of a disused mine there will be climbing-irons to get down by. This stump seems fairly secure. I want you to take a half-hitch round it, and pay out the rope till I find a foothold. When you feel the rope slacken keep on paying out gently. If I jerk it twice in quick succession haul up."

Dick knew that it was useless to expostulate. He could only follow his friend's instructions, and, as Reginald disappeared over the edge of the chasm, he kept the rope well in check. But before he had paid out twenty feet he felt the strain relax.

Slowly he continued to ease off the rope till quite a hundred feet had been let go. Although the exertion was slight the moisture stood in great beads upon Dick's forehead.

Suddenly the rope was jerked out of Tresillian's hands. He heard a stifled cry. Then as he strove frantically to check the swiftly running coil he felt that the strain had ceased. Then the dreadful knowledge dawned upon him that the rope had parted and Reginald had fallen to meet a terrible fate on the floor of the stupendous abyss.

Scarce knowing what to do, Dick stood helpless. His bewildered mind was trying to form some plan whereby he could aid his comrade—if he were still alive.

His agonised thoughts were rudely interrupted, for a pair of strong hands grasped his ankles; another gripped his throat, and a man's knee was thrust violently into the small of his back.

Before he could utter a sound, Dick was lying on his back with his limbs bound so tightly that he could scarce writhe in his bonds.

In the starlight he could see that his captors were three stalwart men, but their features were concealed by thick beards and the turned-down brims of their hats. They were talking rapidly and in low tones in a language that was quite unintelligible to him, though it was evident that they were arguing as to what was to be done to their prisoner.

In a vain hope for the aid that was not to be forthcoming, Tresillian shouted as loudly as his parched throat allowed, but ere the echoes died away one of the men lifted him as easily as if he were a child and bore him towards the mouth of the shaft.

For a moment Dick felt himself being held over the brink of the horrible pit, then fear held him spellbound.

Slowly his captor leant over the abyss. Dick realised with a thrill of indescribable dread that 'twas impossible for the man to regain his balance.... Then, clasping his prisoner in his powerful embrace, the fellow dropped into space.

CHAPTER VII

DON MIGUEL O'ROURKE

"Four bells already, Stubbs?" asked Holmsby, sitting up in what he imagined to be his bunk. Then he began to realise that he was not in his cabin on board the Tremendous, and that it was not his marine servant warning him for duty. Instead he found himself in a cot in a small cubicle, with Tresillian lying on a folding bed groaning most dismally; while standing by the door was a short, swarthy-looking man of obviously foreign descent.

"Where am I?" asked the young officer wearily; then, his attention drawn to his comrade's moans, he demanded fiercely, "What have you done to my friend?"

"There is no need to rise, Mr. Holmsby," exclaimed the stranger peremptorily. "Mr. Tresillian is in no danger. He is merely labouring under the effects of an anæsthetic—even as you were till within a few moments ago."

Obediently Reginald fell back upon his bunk. Somehow he had no inclination to do otherwise. So he lay and pondered, trying to recall the events of the night and endeavouring to find some reason for his presence in bed. Then came the awful recollection of a struggle with an unseen antagonist in the depths of the vertical tunnel; his vain efforts to prevent himself being torn from his precarious foothold; the indescribable sensation of finding himself falling headlong ... and then merciful insensibility.

Almost dreading to make the experiment, Holmsby drew up first one leg and then the other. Thank heavens, they appeared to be sound. His arms, he knew, still possessed their muscular action. Perhaps, after all, in his fall he had not sustained any serious injury.

"I wonder who that little Johnny with the turned-up moustache is?" he thought. "Evidently he knows who I am, but how?"

Raising himself on one elbow, Holmsby looked at the third occupant of the cubicle. He was barely five feet four in height, yet properly proportioned.

He had the olive features of a Spaniard, with dark brown eyes, straight nose, and rounded chin. His hair was dark and crisp, growing low down on a lofty brow; his mouth was of generous dimensions, his lips thin, while his carefully trained moustache failed to conceal a liberal expanse betwixt his upper lip and nose.

He was carefully groomed. His clothes, well-cut and immaculately fitted, consisted of a dark blue yachting coat and trousers, a soft flannel shirt, and a crimson cummerbund; while spotlessly clean white doeskin shoes encased a pair of violet-socked feet.

"Evidently fond of a bit of colour," commented Reginald. "Yet the fellow doesn't look like a fool. Well, here goes; I'll tackle him. Beastly awkward to find yourself in night-gear when you've to question an utter stranger, though."

"Excuse me, but where on earth am I?"

The unknown regarded his interrogator calmly for a few seconds before replying.

"To the best of my belief, sir, you are not on the earth at all, but two hundred and fifty-nine feet beneath the surface."

The stranger spoke in sibilant tones, with the faintest trace of a foreign accent.

"Then how did we get here?" asked Holmsby.

"Mainly through your overstrained inquisitiveness: also, I regret to say, through an equally unfortunate blunder on the part of some of my servants. But we will defer further explanations for the time being, Mr. Holmsby, for I see that your companion is about to recover his normal condition."

Holmsby turned to his friend. Dick Tresillian had rolled partly off his bunk and was moving his right hand over the floor as if in the act of writing.

"Ten thousand fiends take the Cash Account!"

In spite of himself, Reginald smiled at his chum's antics and exclamation.

"Mr. Tresillian, like yourself, suffers from an excess of zeal at times," exclaimed the stranger languidly. "I have heard it said that your Government business methods are of the most antiquated description, and unnecessarily complicated into the bargain. Your friend evidently wished to corroborate my assertion.... Kindly shake him by the shoulders and he will be himself once more. We must excuse the deficiencies of your wardrobes."

Holmsby obeyed, and in a few moments Dick was awake and striving to collect his thoughts, even as Reginald had done.

"I will now leave you two gentlemen to the pleasure of your own company," remarked the unknown. "After your six hours' sleep perhaps a little refreshment will be acceptable. Meanwhile will you do me the honour?" and producing a gold cigar-case from his pocket the speaker with a courtly bow offered it to Holmsby and his comrade.

As he opened the door the stillness of the room was broken by a loud roar—the united outburst of machinery working at high pressure and the surging of the waves in a confined space. But on closing the door after him the stranger completely shut out all noise once more. The walls of the building, though thin, were absolutely sound-proof.

"Well, we've certainly stumbled upon something remarkable," observed Dick, as he proceeded to light his cigar.

"Stumbled into it, you mean," corrected Holmsby, who could not help noticing that the desire to smoke—usually the last taste in a person recovering from the effects of an anæsthetic—was perfectly normal. "But what have they done with our clothes?"

"Goodness only knows: and to think that we've been in a state of insensibility for six hours. But I say, Rex, old chap: what happened to you after you began to descend the shaft?"

The two comrades exchanged the account of their experiences, without being able to satisfactorily explain how they escaped being dashed to pieces in the tremendous drop down the yawning pit.

"No, I can't understand it," concluded Holmsby. "But, by Jove, before I leave this place I'll know why. It also puzzles me to know how that polite little foreigner got hold of our names."

"From our clothing, perhaps."

"From yours, possibly; but I make it a point never to have mine marked with my name. Perhaps we 'babbled o' green fields' in our sleep, or in other words, talked shop. I know for a fact that you did."

At that moment the door opened and a man entered bearing the two comrades' clothes. Without saying a word he placed them on separate chairs and withdrew.

"As silent as the tomb," commented Tresillian. "I wonder if that's one of the fellows who tackled us. However, let's dress and we'll feel more at home."

Their clothes had been carefully brushed and pressed, but, in place of the stout boots in which they had set out, two pairs of doeskin shoes with rubber soles and heels had been brought in to them. Their revolvers had, however, been removed from the pockets of their clothes.

Hardly had they finished dressing than the same man who had brought their clothes reappeared with a tray on which were rolls, butter, eggs, Cornish cream, hot milk, and coffee.

"Gracious! Do they run a model dairy in the bowels of the earth!" ejaculated Tresillian. "Come let's set-to, for I'm as hungry as a hunter."

After breakfast the comrades began a systematic examination of their room. It was about fifteen feet in length and twelve in breadth, the height being about nine feet. With the exception of the door there were no other openings, windows and ventilators being apparently unnecessary. The walls were of a hard resounding substance resembling porcelain, which Tresillian, from his professional knowledge, recognised as "Uralite"—a composition used largely in the construction of light, yet strong fire-proof buildings. The floor consisted of solid rock covered with canvas. Tresillian tried the door. It was locked.

"Queer sort of lamps," remarked Dick. "Apparently electric, though I cannot see any wires."

"Be careful," cautioned Reginald, as his companion grasped one of the glass globes that were placed on brackets on the walls.

The warning came too late. Dick seized one of the globes and lifted it from its shelf. There were no wires.

Even as he did so Tresillian clapped one hand to his eyes exclaiming, "I'm blinded!"

Instantly Holmsby dashed across the room, took the glass from the hand of the unlucky investigator, and replaced it on the shelf.

"How goes it?" he asked anxiously, for Tresillian still kept his eyes covered.

"I hardly know. I was trying to discover whether it was a carbon lamp and the beastly thing seemed to snap the optic nerve.... But it's getting better, I think."

"Still making unfortunate discoveries, Mr. Tresillian?" asked a suave voice, and, wheeling, Holmsby found that the mysterious master of the subterranean home of modern magic had noiselessly entered the room. "I ought to have warned you of the risk of tampering with the lighting arrangements of this apartment. Pray, allow me."

Taking a small instrument resembling an egg-cup from his pocket the unknown held Dick's head with one hand and vigorously massaged his forehead. Tresillian afterwards confessed that it was like the application of a freezing mixture; but in a very short space of time his eyesight was restored to its normal state.

"Now, gentlemen, we will discuss the situation," remarked the stranger, motioning to Reginald and Dick to seat themselves. "I fear that I owe you an explanation."

"To come more to the point," said Holmsby, with more impatience than discretion, although his anxiety might be regarded as being sufficient to justify his unintentional rudeness. "Are we to be detained here against our will? Why were we subjected to an unwarrantable attack by your men? Were you justified in so doing?"

The unknown raised his hand in a sort of dignified protest.

"Really, Mr. Holmsby, you overwhelm me with a torrent of questions," he remarked in even tones. "Please remember that I am master here, and need not reply to a single question unless I choose. You complain that you have been assaulted and forcibly detained here: is not that so? Good: that is your view of the matter. Now listen to mine.

"I am not going to mince matters, for no useful purpose will be served thereby; so I tell you that I mean to detain the pair of you until the preparations for the work I have in hand are complete."

"This is an outrage—an abominable outrage," exclaimed Holmsby.

"Undoubtedly, but you see the punishment fits the crime; but to proceed with my explanation. First let me introduce myself as Don Miguel O'Rourke. Perchance the name is familiar to you?"

"Oh yes," replied Reginald. "Then you are the ex-President of the Republic of Calderia?"

"At present I am the ex-President," assented O'Rourke, with a courtly bow. "But what I hope to be in the future remains to be seen."

It was not so many years ago that the internal dissensions of the South American Republic of Calderia were the talk of the civilised world. President O'Rourke—a descendant of the famous Irishman who, with Cochrane, O'Higgins, and other British half-pay officers, had aided the South American colonies of Spain to throw off the tyrannical yoke—was no doubt a most capable ruler; only, he lived before his time. Educated in London, Paris, and Seville, he showed promise at an early age of exceptional ability, and at twenty-five found himself installed in the Presidency of Nalcuanho, the capital of Calderia. His regime was strictly impartial, but his reforms were either regarded as too advanced by one section of the Calderians or else not sufficiently sweeping to meet with the approbation of the ultra-progressive party. Then, with the characteristic swiftness of the South American temperament, came a revolution. O'Rourke had to flee, taking refuge on board a Dutch man-of-war that happened to be lying off the coast on her voyage to Surinam. Ere long the want of the ex-President's acumen began to be felt by both parties, although a section of the Extremists retained its hostile policy. Calderia called for its former ruler—but called in vain. Don Miguel O'Rourke seemed to have vanished off the face of the earth—now he stood face to face with Sub-Lieutenant Reginald Holmsby in the depths of a Cornish mine.

"Now to resume my explanation," continued O'Rourke. "I came here and bought a piece of ground in this county, including any minerals that might be lying underneath the soil. It is well known that under Sampson's Down is a mine that years ago was flooded out by the sea. I found that my anticipations were realised; the place was admirably situated for the purpose of conducting various experiments and scientific research. Naturally I wished to live in obscurity, but as far as I know, I broke no law of the country that had given me shelter. The place is even open to examination by your Board of Trade Officials and Inspectors of Mines, although, mind you, I did not go out of the way to show them the means whereby I could descend the shaft. Three or four times they troubled me with their attentions, till finding nothing but an apparently ladderless pit without machinery for ascending or descending, they regarded me as a kind of recluse or even a harmless madman—and left me severely alone.

"So far, so good. My work progressed, and I succeeded in perfecting machines capable of travelling either in air or under water—practical amphibians, in fact. But, concerning this portion of my narrative, I have said enough for the present. Then it came to my knowledge that two of my most implacable opponents had almost succeeded in tracing my hiding-place. Their avowed object was either to take my life or to destroy the work I had in hand, which they rightly guessed was to further my plans for recovering my position in Calderia.

"Naturally I took due precautions; but, owing to a blunder on the part of my men, you were mistaken for the rascals——"

"I think we can enlighten you on the movements of your enemies," said Holmsby, and he proceeded to give a description of the encounter with the two foreigners at St. Piran's Round.

"You certainly did me a good turn, though perhaps unconsciously," remarked O'Rourke. "But, on the other hand, what do I find? While you were lying unconscious, under the effect of a certain drug that by inoculation instantly produces utter insensibility, an agent of mine brought me word that an officer of the Naval Intelligence Department, accompanied by an assistant, had been sent down to report on my movements. Why? I know not. In all my nocturnal excursions I have carefully avoided passing over military stations, in spite of reports to the contrary that from time to time have appeared in the papers. There is no law in England prohibiting a man from constructing an airship, aeroplane, or submarine, provided he conforms with the Foreign Enlistment Act and measures of similar import. At least, if there be, I've never heard of it. Now, suppose my secret reaches the ears of the British Admiralty: my work would be totally undone; unscrupulous so-called inventors would steal my plans, my inventions, my brains, and claim the credit. Therefore, since you have fallen into my hands, I hope you will realise the importance of my resolve to keep you until I deem it safe to do otherwise."

"I quite see your point, señor," said Reginald calmly. "But I trust you realise that by detaining us against our will you make yourself liable to severe penalties—illegal imprisonment is a serious offence, you know."

"I am perfectly prepared to accept that risk," replied O'Rourke, as he lit a cigarette. "'Tis but a matter of a few days."

"In a day or so our disappearance will be noticed and a search party will be sent out."

"They may be fortunate: quien sabe?" rejoined the ex-President with a deprecatory shrug. "But now, gentlemen, pray be sensible. Make yourselves at home, as it were. If you like I can materially aid your mission by showing you the wonders of Sampson's Mine. The knowledge will be invaluable to you, and you have my full permission to make whatever use of it that you may think fit—when the time comes. Come now, your hand on it."

There was something about Don Miguel O'Rourke's magnetic personality that Reginald and his comrade found impossible to resist. Both men rose and held out their hands.

"Capital!" exclaimed the Calderian approvingly, as he grasped their outstretched hands in turn. "Now, gentlemen, this way. The secret wonders of Sampson's Mine are at your service."

CHAPTER VIII

A MODERN MAGICIAN

"Do not hesitate to ask any questions, gentlemen," remarked Don Miguel. "But, on the other hand, do not take it in a wrong light should I be compelled, for my own sake, to withhold any information that I may deem prudent to do so. Here you see some strange-looking objects."

Their guide pointed to a small glass case on the wall of the room, in which were several indiarubber discs, each with a fine metal point projecting slightly from its centre.

"They look like vacuum arrow-heads—the kind of toy I used to play with as a small boy," said Dick.

"They are certainly meant to adhere to the palm of one's hand by suction—they are injectors. The fluid—composed of an extract from the deadly poisonous upas tree—passes through a minute tube in the needle. The operator merely makes one of the discs adhere to the palm of his hand and the faintest puncture in the skin of the person operated on is sufficient."

"Good heavens! Do you mean to say you kill people in that diabolical fashion?" exclaimed Tresillian.

"If that were the effect of those implements, neither of you would be here now," replied O'Rourke. "The most deadly poison can, under the fostering influence of science, be made to act beneficially to mankind. Thus, one injection of that liquid produces total insensibility. Its application is not accompanied by that horrible strangling sensation produced by the use of chloroform, neither are the after-effects so distressing—-in fact, there are no after-effects, as you must have realised when you smoked those strong Havana cigars."

Opening the door, Don Miguel motioned to his involuntary guests to precede. They found themselves in a large brilliantly-lighted cave, measuring nearly one hundred yards in length by about thirty in width, the roof arching irregularly to a height of nearly fifty feet. The floor for nearly half the length of the cave was smooth and gradually sloping, but a rough wall, six feet in height, hid the remaining portion from the sight of the two comrades. The nearest part of the floor was occupied by several machines all running at high speed and emitting a deep hum, but neither Tresillian nor Holmsby could discover their motive power. There was a remarkable absence of belts and shafting; each machine seemed to be actuated independently of the others, while one man at each seemed sufficient to control the whirling complicated mass.

"What are those lamps?" asked Tresillian, pointing to one of the globes that had previously been the means of nearly blinding him.

"My own invention," replied O'Rourke, raising his voice above the roar of the machinery. "That I will explain later. Now be careful where you tread."

Throwing open a thin sound-proof door in the wall of the cave the Calderian entered, waited till his guests had followed, and closed the door. The place was pitch dark and as silent as the tomb.

"Be careful," he cautioned. "There is a pool of water just beyond where you are standing. Now, look upwards."

The twain did so. Far above their heads they could discern a small circular disc of pale light, through which a star was faintly visible.

"The mouth of the shaft: two hundred and fifty odd feet deep. You certainly were not devoid of pluck to attempt its descent, Mr. Holmsby, but at the same time I cannot congratulate you upon discretion. Had it not been for the action of my men you would assuredly have been dashed to pieces, for the shaft is only partially laddered, and the rungs are quite rotten in places. As it was, both of you finished your descent in this pool of water, and that was the reason why you found yourselves in bed."

"But how——?"

"Never mind that question at present. I know exactly what you were going to ask. The means of ascent and descent I will tell about in due course."

"It's perfectly quiet here," remarked Reginald. "Yet I could hear the roar of the sea from above."

"Quite possible. At that moment the sound-proof door must have been open for some purpose, although we never prolong that operation. It is to my advantage to stifle any sound that might lead to the discovery of my subterranean workshop."

Re-entering the main cave Don Miguel led the way towards the farthermost recesses. Beyond the stone wall the floor was several feet lower, and here were rows of retorts glowing in an electric furnace, while on a long bench were hundreds of small cylinders, apparently made of earthenware, surrounded by an aura of pale blue light.

"What do you imagine this to be?" asked O'Rourke, picking up a spherical piece of iron from the floor and handing it to Holmsby.

"Looks like an obsolete twelve-pounder shell," replied the sub-lieutenant, handling the metal with evident distrust.

"That is exactly what it is," agreed the ex-President. "See, I remove this plug and you will find water inside. Now, watch."

Drawing on a pair of insulated gloves, Don Miguel took one of the small earthenware cylinders from the bench, deftly inserted it in the iron sphere, and replaced the plug. Then, even as the two Englishmen watched, the mass of iron began to rise, slowly and surely. Up and up it went till it bumped lightly against the crown of the arched cave.

Spellbound, the comrades gazed at this inexplicable phenomenon until Holmsby gasped, "You've discovered something wonderful, by Jove! The force of gravity is absolutely overcome." The inventor beamed with self-complacent pride.

"'Tis the most important discovery of the age," he replied. "Now what do you think is the force that enables a heavy body to be lifted by a self-contained agent? Well, you will never guess: it's a secret compound which I have called 'Helia,' and to be brief it is an extract from the by-products of radium.

"Probably you are aware that immense quantities of pitch-blende—approximately eight tons—are required in order to produce one gramme of radium chloride. A decade ago the total quantity of radium known to be in existence was less than a quarter of an ounce. Now I have found that helia, which is compounded in fairly generous quantities from pitch-blende, when brought into contact with sea-water produces a gas that has approximately a thousand times as much lifting-power as an equal quantity of hydrogen. Unfortunately the constant waste of substance and energy in helia is quite noticeable—a contrast to the non-apparent diminution of radium—so constant charges have to be used in order to keep a heavy body afloat in the air. You will observe that the metal globe is already showing signs of returning to earth."

"Wonderful!" was all that Reginald could exclaim, while Tresillian was quite beyond words.

"I also use helia in conjunction with other gases for the purpose of producing light. Each of those globes contains sufficient light for six weeks without recharging, the substance being contained in a vacuum in order to still further reduce the natural leakage. Now, here is another object to which I wish to call your attention."

Don Miguel held up for inspection a metal case about four inches in length, with one concave face. To it were attached four broad straps provided with buckles.

"Looks like a kind of military water-bottle," remarked Reginald. "But ten to one I'm wrong."

"You are," agreed O'Rourke. "This receptacle is a man-lifting apparatus, and contains sufficient helia to enable a person to leap fifty feet in the air. It is quite possible to increase the size of the charge, but then the danger arises that the lifting-power would be too great, the user might lose his head and, when at a great height, release too much helia with disastrous results. As a matter of fact just enough is used to counteract the force of gravity."

"Then that is how your men descended the cliff?"

"You saw them?" asked Don Miguel.

"Yes, the other day when we were lying off the cove in a fishing-boat."

"The incident was never reported to me," said the ex-President meditatively. "I must inquire further into this, for a public exhibition of the important force at my command is the last thing I wish for at present. Do you know, Mr. Holmsby, that you owe your life to this invention? One of my men seized you just as you were about to descend to a rotten step in the shaft ladder. Even the rope would not have saved you, since your strength would have been exhausted long before you climbed to the surface. You were rendered insensible by inoculation, and brought down—with more force than desirable, I fear—while your companion was, owing to the misunderstanding which I have already explained, subjected to the same treatment."

"That is what I wanted to know," said Holmsby. "I was just conscious of being dragged from the ladder and falling into space—then unconsciousness. But, by Jove, of what incalculable service would that invention prove to an aviator."

"Undoubtedly. As a matter of fact I cannot claim to be the sole originator of the discovery. Waechterlinck in 1910 and Hauptmann in the following year nearly stumbled upon the use of helia, but each in a desire to circumvent his rival, issued a treatise on the subject ere their researches were materialised. In the interests of humanity I even went so far, at the great risk to the success of my great mission in life, as to hint of my discovery to the principal Aero clubs of Great Britain, France, and the United States—but in each case my offers were curtly declined. No doubt I was thought to be a madman—a common verdict on most of the world's greatest inventors until time has vindicated the truth of their discoveries."

By this time O'Rourke and his two companions had reached the apparent end of the cave. Here a wall of roughly-hewed granite stopped all further progress.

"Beyond this partition is the flooded portion of the mine," explained Don Miguel. "The water stored within is sufficient to run the electric dynamos for sixteen hours per day. For the remaining eight we have to make use of the rising tide, which here attains a height of seventeen feet. You see we are still obliged to press electricity into our service, although before long I hope to have stored sufficient energy in the form of helia to make us independent of dynamic power. Now, gentlemen, behold my masterpiece."

As he spoke O'Rourke thrust aside a sliding hatch on the floor, disclosing a deep vault that was one blaze of light. Kneeling down both Englishmen leant over the edge of the opening. Below them they saw the afterpart of a huge, grey-coloured object that might be either airship or submarine.

"The Amphibian," announced the inventor.

CHAPTER IX

THE "AMPHIBIAN"

With professional eagerness and curiosity Reginald Holmsby gazed at the monster with ill-disguised astonishment. Oblivious of the fact that he was in danger of losing his balance and falling a sheer distance of fifty feet, he remained in rapt admiration at the very brink of the yawning pit.

"Perhaps you would like to make the close acquaintance of my chef d'oeuvre?" asked Don Miguel.

"I should," replied Reginald eagerly.

"Then you must trust yourself to the merits of my gravity-neutraliser," continued the inventor, providing three of the small metal cases from a receptacle fixed to the wall.

In a few seconds the three men were equipped, the device being securely fastened to their backs by means of the straps.

"Be careful not to walk with a springing step—glide rather," continued Don Miguel, as he proceeded to charge the apparatus on Tresillian's back. Reginald watched him curiously.

Opening a small panel by means of a powerful cam-action slide, O'Rourke deftly thrust in a small cylinder of porous clay and instantly sealed it. This done he performed a similar operation with the case strapped to Holmsby's back, and instantly the sub-lieutenant became aware of the upward force of the imprisoned chemical.

"You saw what I did? Good!" exclaimed Don Miguel. "Now do you think you could do the same for me? Otherwise I must send for one of my men."

"I'll try," replied Holmsby, and, following the examples that he had already seen performed, he succeeded in charging the Calderian's gravity-neutraliser.

"Let yourself drop," said O'Rourke, and, without hesitation, though he involuntarily closed his eyes, Reginald stepped over the edge of the pit.

Unfortunately in his grim determination the young officer stepped too eagerly, and instead of falling slowly he rose a good twenty feet in the air, descending some distance on the other side of the opening to the lower cave. Nor were his antics ended on his descent, for mechanically he bent his legs to break his supposed fall, with the result that he again performed a prodigious leap. Eager to aid his comrade, Tresillian made a rush forward, only to find himself soaring upwards. So vigorous had been his "kick-off" that he brushed the roof of the cavern.

"I think I gave you fair warning," remarked Don Miguel without the suspicion of a smile, when the twain had somewhat gingerly gained the floor. "Now, watch me."

With a springless gliding motion the inventor slipped off the edge of the opening. Then, slowly, as if being lowered by an invisible wire, he descended to the lower level. Profiting by his example, the two Englishmen followed.

"There is no necessity to empty the charges," observed O'Rourke. "They are sufficient to last four hours at the least—but be careful to secure the belts round the iron bar. Otherwise we would have to have recourse to the somewhat unpleasant operation of being hauled up by a rope."

Having taken off and secured the gravity-neutralisers, the two Englishmen walked up to the mysterious vessel, which they had beforetimes seen and heard about. Now it rested in front of them: its wondrous secret was to be theirs.

Its fabric consisted of a smooth, rigid metallic substance, lined with thin asbestos sheeting to withstand the effect of expansion by heat without the necessity of having to provide safety valves for the compressed gas. The bows were somewhat snub, the afterbody thinning off gracefully to a sharp point. Right through the centre of the bow projected a shaft, on the end of which was a two-bladed metal air-propeller.

Aft were the horizontal and vertical rudders and a four-bladed propeller for use when submerged. There was no "nacelle" or car, but in the place of a conning-tower on the highest part of the convex surface a long narrow metal hatch, projecting barely three feet beyond the outer skin, extended fully ten feet in a fore and aft direction. This raised part was provided with glass inspection-holes or scuttles.

The craft lay on a cradle that had been hauled up an inclined plane, the slipway disappearing beneath the surface of the water that covered the farther-most recesses of the lower cave, but a constant agitation of the water showed that there was direct communication between it and the open sea.

This much Holmsby took in with the eye of an expert, but there were several points on which he could not find a satisfactory solution.

"How can that huge envelope—for such I must term it, successfully withstand the pressure of the water when submerged, and also possess sufficient lightness—even taking into consideration the lifting-power of your helia—to rise in the air?" he asked.

"The outer skin is not intended to be subjected to any great strain under water," replied the inventor. "It merely contains the helia, being divided into ten gas-tight compartments, six of which, when charged, being sufficient to raise the ship. The others are to be used in case of emergency should a leakage occur. Inside the outer fabric is the submarine proper—built of enormously strong plates of duralium. Supposing the Amphibian is in the air and wishes to dive beneath the sea. The helia is allowed to escape and the airship sinks till it rests on the surface of the water. Unfortunately it is not yet possible for a vessel to make a direct dive from the air into the sea or vice versa—unless, of course, she is an utter wreck: but that is outside my subject. So the Amphibian has to rest on the surface for a few minutes while water is rushing into the compartments of the outer envelope to take the place of the expelled helia. The pressure of the water is resisted by the walls of the submarine, while at the same time the presence of a homogeneous fluid inside and outside the outer skin of the airship preserves it from injury. Diving is performed by the action of the horizontal rudders, the submerged craft having a slight reserve of buoyancy."

"But when the vessel has to ascend from beneath the surface?"

"The process is practically reversed. The introduction of a cylinder of helia into each of the six compartments causes the gas to expand in contact with the salt water, and the tremendous lifting force is brought into action. Simultaneously the water is expelled through the automatic valves, and the vessel immediately soars skywards."

"I notice that you have two propellers: the one for submarine work is not, of course, used in air, but how about the aerial propeller when the vessel is submerged? A twin-blade of comparatively large area would be a hopeless drag in the water, besides being easily damaged should it come into contact with any substance that would not otherwise cause harm in the ordinary course of events."

"I agree with you. But I have already made due provision for this contingency. Before the Amphibian dives the aero-propeller folds back upon the shafting, and the whole is withdrawn into the outer envelope."

"If it is not troubling you too much," said Tresillian, who hitherto had been listening and observing in silence, "I should like to ask you one or two questions."

"As many as you like: your interest is a source of satisfaction to me and a testimony to my work," replied Don Miguel grandiloquently.

"But are you not afraid to explain all this, knowing the nature of my visit?" asked Holmsby.

"Afraid? No!" exclaimed the inventor, with the utmost conviction. "You have yet a lot to learn ere you master the supreme secret of the Amphibian. But, to speak bluntly, I should not be at all surprised if your Admiralty did not make a hard shot at it. You English were ever good at copying. History proves it. You 'adapted' your vaunted British bayonet from the French; from the same nation you copied the lines of their fastest frigates in the days of Wooden Walls; in the submarine you improved upon an American invention; you waited till the first aeroplanes came to something like perfection ere you picked the brains of the American Wright Brothers. It's a nice policy to wait and see, but hardly honest. However, that's neither here nor there at present—what did you wish to ask me, Mr. Tresillian?"

"If the outer skin completely encloses the submarine, how do you manage to steer the Amphibian under water; and how do you contrive to navigate her in the air? Surely it is essential to be able to observe what is taking place beneath the craft?"

"You will be better able to understand my reply if we board the Amphibian, Mr. Tresillian; so we may as well do so at once."

CHAPTER X

THE WONDERFUL NUTSHELL

"We'll find a ladder on the starboard side," continued O'Rourke. "My men are still at work with the finishing touches, besides repairing some slight damage sustained during our last experimental trip."

As the three men made their way under the tapering stern Holmsby caught sight of a familiar object lying on the slipway. It was the anchor and cable of the fishing-boat they had hired.

"That is the cause of our last mishap," remarked the inventor, pointing to the anchor. "Our stern propeller bracket fouled this kedge as we were returning to the cave."

"So I believe," replied Reginald. "It is the anchor of the boat we were in. You nearly towed us beneath the surface."

"Oh! Might I ask what you were doing in Sampson's Cove?"

"Keeping a look out for your return," replied Holmsby frankly. "You see we were not disappointed."

"Your curiosity cost us several hours of labour," said Don Miguel. "However that is now a thing of the past. By the bye, here is the tunnel communicating with the open sea. When I bought the place there was only a small opening, but with the aid of dynamite and four skilled Italian divers—who were brought here without knowing where they were—we soon contrived to enlarge the tunnel to suit my purpose. The materials for building the Amphibian, together with the necessary plant, were conveyed to the cave in a submarine of an antiquated pattern that I bought at a sale at Richmond Navy Yard, U.S.A. We still use the submarine for similar purposes. At present she is lying in a cave to the left of this tunnel."

Ascending a ladder that had been temporarily placed against the bulging sides of the Amphibian, the three men gained the long, narrow raised platform. Here Holmsby noticed that there were sockets fitted to receive rails and stanchions, although the latter had been unshipped in order to facilitate the vessel's passage through the submarine tunnel.

"You are now standing upon part of the Amphibian that cannot be described as belonging to either the aerial or the submarine portion. It is, in fact, a sort of combined conning-tower, mechanical appliance chamber, aerial observation station, and emergency compartment. It extends right through the central portion of both airship and submarine, and, in case of stern necessity, when the vessel is submerged, the whole can be released and brought to the surface. When in the air this deck forms a promenade, and, as you can see by the mountings, we are able to fit a light pair of quick-firing guns fore and aft."

Throwing back a metal hatch, lined with indiarubber, Don Miguel motioned to his guests to descend.

"You are now in the uppermost storey or the conning-tower," he continued. "There are observation scuttles on all sides, each commanding a clear view above the turtle-deck. This lever controls the elevating planes; this the vertical rudders. Here is the switch that actuates the submarine propelling machinery, while close to it are the appliances for feathering the aerial propeller or starting its shafting as the case may be."

"What is the motive power?" asked Holmsby.

"Radio-electricity: we carry a supply sufficient to take the Amphibian for a distance of 12,000 miles, or, roughly, half the circumference of the globe. Under water the radius of action would be about one-fifth, or enough to take the vessel across the Atlantic."

"These discs," he continued, pointing to ten red-capped pushes of about half an inch in diameter that were ranged in two rows on a switch-board, "are the termination of the tubes through which the helia charges are sent to the respective ballonettes of the airship. Until ready for use the charges are stored in an air-tight magazine underneath the floor you are now standing on. To keep them perfectly dry is absolutely essential: indeed, I shudder to think what the effect would be if water came in contact with that vast store of potential energy."

The second storey was, in the absence of scuppers, lighted artificially. Here were the water-tight doors communicating with the fore and aft parts of the submarine, and also the officers' quarters.

Opening one of the slides Don Miguel showed the two Englishmen the cavern-like interior of the forepart of the metal-sheathed vessel.

"Here the crew, nine in number, have their quarters. When submerged the air is purified by oxygen; when the Amphibian is above the surface fresh air is supplied by means of automatic ventilating pipes leading through the gas chambers of the airship," observed the inventor. "Here, too, are the torpedoes for submarine attack, eight of them charged with a high explosive and having an effective range of 8000 yards, being stored under that raised bench. You can now see the shafting of the aerial propeller. On either side of it are the two torpedo tubes."

"Have you no means of using aerial torpedoes?" asked Reginald.

"Yes, those will be shown you shortly; meanwhile you might as well have a look at the afterpart of the submarine, for there the propelling machinery is placed."

Retracing his way to the central section, O'Rourke carefully secured the water-tight panel. Then, crossing to the opposite side of the compartment, he opened a similar door.

"Is that all the propelling machinery?" asked Holmsby in surprise, as a small six-cylindered motor met his eye.

"More than sufficient to drive the Amphibian" replied the ex-President, with a smile. "If you could but see those running at 2000 revolutions per minute."

"But surely that is impossible as regards the aero-propeller. And, besides, the shaft ends here, whereas the aero-propeller is for'ard."

"Quite so," assented Don Miguel. "Part of the aero-shaft passes outside the central compartment and is geared up to the main shafting for the submarine propeller, thus giving the former a speed of not more than 250 revolutions. Also, had the shafting of both propellers been direct it would have to pass through the central compartments, and in that case it would be impossible to use that portion of the vessel as an emergency compartment. Now we will make an inspection of the lowermost storey, and then I think you will have had a very general idea of my masterpiece."

Descending the third ladder the two Englishmen found themselves standing upon a slightly concave floor, this compartment also being artificially lighted.

"These are four thick plate-glass observation holes at your feet," explained O'Rourke, "only as the Amphibian is on the slip we have to keep them covered by metal plating. Through them we can, when in the air, command a distinct view of all that is going on beneath us. Here is the bomb-dropping gear. Observe these indicators. This one gives you the speed of the ship through the air, to which must be added or subtracted, as the case may be, the velocity of the wind. Thus, suppose we are travelling at 30 miles per hour in a northerly direction against a northerly wind of 15 miles per hour. That means that we are actually moving over the ground at a rate of 15 miles per hour. That is simple enough. Now, in addition, when dropping a bomb, we have to take into consideration the motion imparted to the projectile by the speed of the airship. Thus, suppose we were to drop a bomb when travelling at 60 miles an hour. The instant the missile left the mouth of the dropping apparatus it would have a tendency to travel in a horizontal direction at the same speed, as well as being taken earthwards by gravity. In a few seconds the latter force completely overcomes the former, but in its flight the missile's course is that of a parabola. This indicator, therefore, enables us to automatically make due allowance for the horizontal motion of the airship and ensures the bomb hitting the mark. Now I think I have shown you all that I can possibly do within the bounds of discretion, so we will now return to the quarters temporarily assigned to you."

Without another word Don Miguel led the way to the place where they had left the gravity-neutralisers. Donning these, the Englishmen succeeded in following their guide to the upper cave.

Here a man approached the ex-President and, with a salute, handed him a sealed envelope.

Don Miguel tore it open and read the contents. As he did so a deep flush overspread his olive features.

"Gentlemen, your term of detention will be shorter than I anticipated," he exclaimed. "I have just received information that Calderia is threatened by its powerful neighbour the Republic of Talpico. Now is my chance: to-night the Amphibian leaves for the seat of hostilities. Ere she leaves you will be escorted to the summit of the cliffs and allowed to return to Penkerris. Meanwhile, as I have urgent work on hand, I must ask you to return to your quarters until I am at liberty to entertain you."

"Look here, Dick," exclaimed Holmsby, when they found themselves alone, "I'm going to see this thing through."

"What do you mean?"

"Why, haven't I a sort of roaming commission? We'll have a cruise in the Amphibian. You can square the matter all right with your chief, and we'll have an exciting voyage, I can assure you."

"I'm game," replied Tresillian resolutely. "But will Don Miguel O'Rourke consent?"

"Where there's a will there's a way," said Reginald, his eyes fixed upon the glass case that hung upon the wall. "I'll ask him. If he consents, so well and so good—if he does not, I'll compel him by fair means or foul to have two Englishmen aboard the Amphibian on her voyage to Calderia."

CHAPTER XI

HOLMSBY GAINS HIS POINT

"Fair means or foul," repeated Dick slowly. "What do you mean?"

"What I said. Is there anything to prevent us threatening him? If needs be we can use one of these injectors, make him insensible, barricade the door, and hold him prisoner till he submits to our terms."

"Won't do, Rex, my boy," replied Tresillian. "Think it over. It savours of treachery, flinging yourself upon an unsuspecting man and rendering him insensible——"

"But he did not hesitate to serve us the same," expostulated Holmsby.

"Acting under a misapprehension. Remember he freely admitted his error."

"Well, go on."

"Besides, Rex, you've forgotten one incident that makes this intended coup de main impossible."

"What was that?"

"We shook hands with him."

"Oh!" There was a sincere tone of contrition in Holmsby's exclamation. He now realised, through his companion's arguments, that any course that necessitated force or coercion would be unworthy of the conduct of an English gentleman. Hitherto in his impulsiveness he had overlooked this fact.

"Hang it all, man," he continued. "You're right. But we must manage it somehow. Think, man, think as you never did before and find a feasible plan for getting on the right side of Don Miguel O'Rourke."

Thus adjured Dick Tresillian tried to form some idea of the best means of diplomatically tackling the ex-President. But though he was on his mettle the young Civil servant was bound to confess that his train of thoughts led to no satisfactory solution of the problem.

"Come on, come on!" exclaimed Holmsby impatiently, after he had sat in a chair for a full half-hour. "Something must be done. Let's review the situation: violence barred; strategy doubtful. Here! Can't we manage to stow ourselves on board?"

"We might, but to what purpose. O'Rourke would then be perfectly justified in setting us ashore on the first convenient land: convenient no doubt to him, but mighty awkward for us. We might be hopelessly stranded, thousands of miles from home, with scarce ten pounds between us, and nothing gained as far as knowledge of the Amphibian's capabilities as a fighting machine are concerned. My own opinion is that O'Rourke is a perfect gentleman, but if angered he would prove a nasty customer to tackle."

"Well, we must see what we can do by asking him point-blank. That's the only way I'm——"

Holmsby's words were left unfinished, for at that moment the door was thrown violently open and O'Rourke rushed in, thrust the door to, and attempted to wedge it with his foot. But all to no purpose—with an irresistible heave the door was wrenched from its hinges, and a great hulking man, his face inflamed with passion, burst into the room, brandishing a heavy, keen-edged machete in his hand.

Without taking the slightest notice of the two Englishmen the would-be murderer bounded upon the ex-President, snarling the while like a beast of prey.

Raising a chair with both hands the agile Calderian attempted to parry the savage thrusts of his opponent. It was touch and go, for in his fanatical rush the hulking body of the attacker well-night swept the lightly-built form of the ex-President from off his feet.

Up went the blade once more. In another instant...

But by this time the two Englishmen had regained their scattered wits, for the sudden and unexpected entry of Don Miguel and his assailant had taken them totally aback. Flinging himself upon the giant, Holmsby grasped the man round the neck and pinioned his right arm to his side, while Tresillian seized the man's wrist in his iron grip, receiving a clean cut in his own arm as he did so.

"Hold him tight!" exclaimed O'Rourke breathlessly, as he slipped from the front to the rear of his assailant.

It was a difficult business, for the man was as powerful as a gorilla, his rage adding to his strength.

Holmsby was on the point of shouting to O'Rourke to help secure the struggling maniac—for that he practically was—when out of the corner of his eye he saw the ex-President dart to the wall-case and extract one of the injecting needles.

Awaiting his opportunity O'Rourke buried the point into the heaving neck of his assailant, and the two Englishmen felt the ponderous carcase, a brief instant before full of strength and uncontrollable energy, grow limp and helpless in their grasp.

"Place him on the floor," exclaimed Don Miguel as calmly as the exhausted state of his frame permitted. Then, "Thank you, gentlemen," said he.

"Good heavens, you've killed the man," exclaimed Tresillian.

"He would certainly have knifed me but for your assistance," replied Don Miguel. "No, he is not dead, though he richly deserves to pay the death penalty. In another hour he will recover his senses.

"Remove him," he added in Spanish, addressing five or six men, who, with their olive features grey with apprehension, had rushed to their master's aid. "When he comes to, place him in irons."

"You're not hurt, sir?" asked Holmsby.

"Hurt? No: but your friend has made the acquaintance of that rogue's machete."

"So I have," exclaimed Dick, for the first time aware that his arm was bleeding freely. "But it isn't much—merely a scratch."

"Let me attend to it," said O'Rourke. "Yes, a clean cut and nothing serious. In a day or so it will heal."

"What, might I ask, caused that man to make such a ferocious attack upon you?" asked Reginald, as the ex-President began to wash and dress Tresillian's wound.

"Caramba, I cannot tell," was the reply. "I had occasion to speak to the man—his name is Jose Alini, and hitherto he has been perfectly satisfactory—concerning the stowage of certain gear: not at all complainingly, be it understood. Without warning he whipped out his machete and rushed at me, and this cabin being the nearest place where I could hope to check his pursuit, I ran for it. Undoubtedly you saved my life, gentlemen, and you will not find Don Miguel O'Rourke ungrateful. Anything in my power that I can do for you I will right willingly."

"Thank you!" exclaimed Holmsby, so emphatically that the inventor started in surprise. "Thank you, Don Miguel. We'll hold you to your word. We have a request to make."

"And that is——?"

"That we may accompany you to Calderia on board the Amphibian, señor."

"Caspita! This is the last thing I expected," exclaimed the South American with undisguised surprise. "Have you weighed the question thoroughly? Bueno! My word is my bond."

"A thousand thanks, señor. We shall be ready to start as soon as you think fit. Meanwhile is it possible to communicate with our friends and our respective Heads of Department?"

"Our wireless telephone will be placed at your service. With it you can speak to my agent in London and he will forward any messages to their proper destination. Or, if you wish, you can write, and I will see to it that the letters are safely posted."

"The first course will be preferable, I think," replied Reginald. "We might get a reply through before we start."

"Then there is no time to be lost, Mr. Holmsby, for we start in less than five hours. It is now four o'clock."

"And the Department closes at five," exclaimed Tresillian. "There is no time to be lost."

"There never is," replied O'Rourke oracularly. "So if you will kindly write out your messages I will be responsible that they are forwarded without delay. Now, gentlemen, I must be off once more, for there still remains much to be done. Meanwhile, remember that once you have put your hands to the plough——"

At half-past eight the two Englishmen were informed by the inventor that all preparations for the voyage were complete and that they could now board the Amphibian.

"There has been no reply to any of your messages," he continued. "I can vouch for it that every one was sent off within twenty minutes."

"In that case we must take French leave," replied Holmsby resolutely. "For my part I can claim that I am acting within my instructions. You, Dick, being here unofficially, must make the best of things."

"I suppose I must. But, candidly, I wouldn't very much mind if I never set eyes on that rotten old office again. Now, I'm ready."

"Here are your revolvers and ammunition, gentlemen," said Don Miguel. "You will pardon my action in temporarily depriving you of these, but taking into consideration the fact that I did not know you as intimately as I do now, the precaution must be regarded accordingly."

In the outer cave the contrast was most marked. The machines had ceased their shrill whirr; most of the lamps had been removed. In the semi-gloom the place looked ghostly.

"We're shutting down the house, you see," explained Don Miguel, with a smile. "Perhaps we may never require to use Sampson's Cave again, quien sabe?"

Descending to the lower cave the two Englishmen found the Amphibian all a-shiver under the action of her propellers, which, at a comparatively slow speed, were being revolved to satisfy the engineers that all was in order. From a scuttle looking for'ard a powerful search-light threw its brilliant white beam upon the surface of the still agitated water. Men were running hither and thither, on deck and ashore, all intent upon the work of clearing away the dog-shores that held the cradle.

"I thought you had nine men for the crew," remarked Holmsby. "There are at least thirty here."

"Three officers—the lieutenant, engineer, and myself—and nine men," replied O'Rourke. "Including yourselves there will be fourteen persons on board. The others remain until the Amphibian is clear of the cave. They will then complete the dismantling of the workshop, seal up the stores, and take their departure in the submarine of which I have already told you."

"Good heavens, what are you going to do with that?" asked Tresillian, as the heavily-manacled form of the ex-President's assailant was led across the cave.

"I have dealt with him already," replied Don Miguel. "He will be taken on board the submarine and placed ashore at a port where he will find it difficult to return to Calderia in a hurry. He will be subjected to no further punishment, I assure you. As a matter of fact, I ascertained the cause of his act of violence: it was mental aberration due to prolonged work at too close a distance from a powerful helia lamp. The man neglected to wear his rubber head-gear, and this was the result."

"Poor brute!" exclaimed Holmsby, then, under his breath, he muttered, "A jolly good job for us anyhow."

"Up with you," said O'Rourke, pointing to the ladder, and in a very short space of time the two Englishmen were standing upon the narrow promenade-deck of the Amphibian. The inventor rejoined them, the ladder was removed, and the vessel was ready for her long voyage.

"All clear?" shouted O'Rourke in Spanish to the men who remained. Receiving an affirmative reply he motioned to his companions to go below.

Here the brilliantly-illuminated conning-tower presented a somewhat different appearance to what it had done a few hours ago. The engineer was at his post, testing the various switches and levers, while his eyes frequently sought the array of indicators above the switch-board; a subdued hum accompanied the slowly-running motors; the oscillation of the whole vessel added to the general aspect of novelty.

"Now we are ready!" shouted the inventor, as he gained the conning-tower and secured the massive, rubber-lined hatch-cover. He had to raise his voice to make himself audible above the din. "Take up your position at those scuttles and you will see the walls of the tunnel quite distinctly.... Now, we're off."

CHAPTER XII

THE "AMPHIBIAN" TO THE RESCUE

A slight jerk, a barely perceptible jar as the cradle slipped down the ways, announced to the interested Englishmen the fact that the Amphibian's voyage had commenced.

Then, as the huge bulk slid slowly into the water, came the sharp hiss of the air that was being expelled from the outer envelope.

The engineer, with his right hand upon the starting-lever, was watching the mercury rise in the submersion indicator. Slowly, yet surely, rose the silvery column till it stood at 14 metres—at which depth the Amphibian was awash. The engineer thrust down the lever till the needle in the dial that recorded the number of revolutions per minute oscillated between 200 and 210, and the craft quivered under the vibration of the powerful propeller.

Yet the Amphibian forged ahead but slowly, guided by the impassive O'Rourke, as he grasped the spokes of the wheel and kept the craft fairly in the centre of the vast tunnel.

From where he stood at one of the scuttles on the starboard side, Holmsby could see the weed-covered wall of the tunnel glide past under the reflection of the powerful for'ard search-light, the displacement of the water causing the long, dark-brown tendrils to agitate like a nest of young serpents.

Suddenly a beam of subdued light flashed athwart path of the Amphibian. Reginald saw that it came from the conning-tower of the submarine which was lying in the side cave, waiting to take off the remainder of O'Rourke's men after the Amphibian had left. Then, an instant later, the wall of the tunnel resumed its unbroken aspect.

Holmsby glanced at the ex-President. Don Miguel seemed unconscious of his surroundings, his whole attention was directed upon the gleaming white disc ahead where the searchlight's rays impinged upon the top and sides of the cavern. Standing slightly below and in front of his chief was the lieutenant, his long, thin hands grasping the lever actuating the elevating planes and rudders. As for Dick he seemed glued to his scuttle, for, in the mirror-like reflection of the glass, Holmsby could see his chum staring at the waving masses of seaweed as if completely fascinated by his unwonted surroundings.

Ere the Amphibian had started on her voyage, Holmsby had, with professional force of habit, looked at the compass. The needle then pointed to "norte cuarto norte-este" (N. by E.); it now showed nearly "Norte-oeste cuarto norte" (N.W. by N.), showing that the tunnel had made a fairly sharp curve of nearly 45 degrees in less than two hundred yards.

Looking aft, Holmsby could see nothing but an opaque body of water; even the churning of the propeller failed to produce any phosphorescent swirl on the agitated water; so, having investigated on all sides, he again directed his attention ahead.

Now, even though it was night, came a faint luminosity, showing that the open sea was not far off, and at the same time the Amphibian began to develop a motion hitherto unnoticed—a kind of combined pitch and roll, though not sufficient to cause the heeling-indicator to register more than 1 degree.

"We are now clear of the tunnel," said Don Miguel, speaking for the first time since the Amphibian had started on her voyage. "This motion is due to the undertow; when we descend deeper we will be beyond its influence."

"It must be fairly rough outside," replied Holmsby, glancing at the submersion-gauge that stood at 19 metres. "We are in fairly deep water. I didn't know such a depth existed so close inshore."

"It's merely a narrow, natural gulley not marked on the charts," replied O'Rourke. "And, as you say, it is blowing not half a gale but a whole gale from the north-east. I was going to ascend, but under the present circumstances I don't think it is advisable—at least till we get a good offing."

Then, bending towards the engineer, he motioned to him to let the motors run at full speed.

Instantly the craft, quivering like a leaf, shot forward; but as soon as she "got into her stride," as Tresillian expressed it, the vibration practically ceased, while the motors purred so easily that conversation could now be carried on with comparative facility.

"I should like to let her rise," continued Don Miguel. "You see we are still in 13 fathoms—hardly sufficient to escape running the risk of being smashed up by a deep-drafted steamer, though I admit the probability is somewhat remote. As it is, we have only 2 metres of water under us."

"The envelope is certainly a disadvantage in that respect," replied Reginald.

"Yes, I quite admit I ought to have reduced the height and given a corresponding increase in length and beam. However, when we are in deeper water, it will not signify. But see, there is a vessel passing over us."

Giving the search-light a slight upward inclination, Don Miguel pointed through the for'ard scuttle. In the powerful beam the two Englishmen could see the wildly-pitching heel of a tramp-steamer as her single screw alternately raced and gripped in the heavy sea.

"No doubt her officers will enter a note in the log to the effect that they passed through a luminous patch in Lat. 50° 15' N.; Long. 5° 25' something W.," said the inventor. "But I wonder if they have any idea of what was but a few feet beneath their keel?"

"She was throwing herself about," remarked Reginald. "But here down below there is no indication of the weather."

"We'll soon have a sample of it, Mr. Holmsby," rejoined O'Rourke. "We have placed a fair space between the Amphibian and the shore, so we'll let her ascend. But be prepared for a bit of a rough tumble: we are bound to have it fairly thick while we are resting on the surface."

For the next few minutes all was in a state of apparent confusion—the officers shouting, men running hither and thither as far as the limited space permitted. The submarine propeller ceased its rapid revolutions; the six helia cylinders were thrust into their respective ballonettes, while under the action of the powerful pumps the surplus water was ejected from the outer envelope.

Like a huge bladder the Amphibian was tossed upon the crests of the mountainous waves, drifting rapidly to lee'ard the while as her crew hastened to manipulate the air-propeller gear. Rolling well-nigh on her beam ends, the giant craft was almost at the mercy of the elements. It was a risky course, for had there been a craft in her path it would have been certain destruction.

"It is thick, by Jove!" exclaimed Reginald, bawling into his friend's ear. "If the aerial part of the programme is not better than the transitory stage I would rather that the Amphibian remained beneath the surface."

"I'll be hanged if I care for it at all," admitted Dick. "This is more than I bargained for. Oh! That was a brute!" he added, as the crest of a vicious wave caught the cork-like Amphibian on her quarter and threw her quite ten feet clear of the water.

"She's rising," replied Reginald cheerfully. "Hold on tight."

"That's what I've been doing for the last ten minutes," gasped Tresillian, as his legs shot from under him for the tenth consecutive time.

Again a wave dashed against the huge bulk, only to flick harmlessly under her. The Amphibian had begun to feel the upward force of the helia, and was now well clear of the surface of the cauldron of seething water.

Still she rocked as the eddying currents of air seemed to smite her on all sides. Then came a sharp detonation as the first cylinder fired, a whirr, and the air-propeller shafting began to revolve.

Bringing the now tractable airship head to wind, Don Miguel allowed his crew to take a well-earned spell ere the south-westerly course was resumed.

"It's the first time we have attempted to rise in a gale," he explained, turning to the two Englishmen. "I don't think I'll try it again, unless under stern necessity. What it must be like ashore, goodness only knows. I pity any aviator or aeronaut who attempts to try conclusions with a sixty miles an hour gale ashore."

With that Don Miguel left them to make a tour of inspection, but having satisfied himself that all was in order he returned.

"Perhaps, gentlemen, you would like a turn on the promenade deck?" he inquired.

Holmsby and Tresillian looked at him in amazement: surely the Calderian was joking.

"There is no danger," continued the-ex-President.

"Danger!" exclaimed Holmsby, bridling at the suggestion. "We are ready, sir, to brave the elements."

"Shall we require oilskins?" asked Dick. "You see we brought none with us."

"I think not," replied O'Rourke. "There are thick coats at your disposal. The night air at this altitude may be somewhat raw. For myself I will go as I am."

So saying the inventor unbolted and threw back the hinged hatch and gained the deck. Unwilling to seek additional protection from the raging elements when their host had scorned to do so, the Englishmen followed holding their caps tightly to their heads in anticipation of a hurricane.

But to their surprise, instead of having to hold on like grim death against a howling gale, they found themselves standing in an almost perfectly calm atmosphere. The stars were shining brightly, and a barely perceptible breeze, warm in spite of the altitude, fanned their faces. Instinctively Holmsby looked for the Ursa Major making the astounding discovery that the Amphibian was heading dead in the eye of the supposed north-easterly gale.

Except for the starlight and the light filtering through the scuttles, the deck of the Amphibian was in darkness.

Holmsby walked to the rail and leant over. Far beneath him, as far as the eye could reach, was a vast bank of rugged clouds, torn here and there with wide ever-changing rifts.

"Have a cigar, gentlemen; it's quite safe," exclaimed Don Miguel genially, as he produced his inseparable gold case. "You will appreciate a weed in this pure and mild atmosphere. Somewhat of a surprise, eh?"

"I suppose we have struck a stratum of calm air?" asked Dick, as he held a lighted match in his upturned hand.

"I think not," replied the inventor, with a smile. "Otherwise these wind-torn clouds would be ramping past us. As a matter of fact, we are at this moment travelling stern-foremost over the earth at an estimated rate of fifty-five miles an hour."

"Great Scot!" ejaculated Tresillian. "Is that so?"

"At present we are travelling through the air at five miles per hour; the propeller is revolving at a comparatively low rate of speed, you will observe, barely sufficient to give the vessel steerage-way. Her direction is against the real direction of the wind, which we estimate at sixty miles an hour. By simple subtraction, we arrive at the fact that our speed over the land—or sea, rather—is practically fifty-five miles per hour in the same direction as the wind."

"I see," replied Dick. "Had the propeller not been working we would be in the position of a non-dirigible balloon floating in calm air notwithstanding the force of the wind."

"Precisely. Once clear of the earth, the wind being free from eddies, there is no danger of being overcome by the wind. It is only when leaving or returning to earth that is dangerous."

"It never struck me in that light before."

"Probably not. But, look, there is a light below us!"

The three men leant over the rail. Nearly half a mile beneath them, betwixt a rugged rent in the apparently stationary clouds, a blinking light seemed to move in the same direction that the Amphibian was heading for, although infinitely quicker.

"A lighthouse!" exclaimed Dick. "A fixed red light and a flashing white one. What is it, I wonder?"

"You've seen it times before, Dick," said Holmsby in mock reproof. "That's Godrevy Light—a white flash every ten seconds."

"I don't remember the red light," replied Dick.

"Perhaps not, it is only visible across the reefs lying N.N.W. off the lighthouse: consequently we are somewhere above that danger."

"You can judge by the speed that light appears to drift ahead of us that we are travelling fairly quick," said Don Miguel. "Already we are half-way across St. Ives Bay."

"Why are we going so slowly and against the wind?" asked Tresillian.

"To give the crew a chance for rest. They've been working splendidly for nearly twenty hours. But we are descending, I fear. If we are not careful we will find ourselves scraping the dirt off your Cornish hills. See, there is another light below us."

"A flare!" exclaimed Holmsby. "Some vessel in distress."

"If that be so we will descend still farther," said O'Rourke decisively. "To aid a ship in peril is a universal duty."

So saying he led the way below, till they reached the lowermost of the central compartments, pausing to give the engineer directions as he did so.

Almost immediately the Amphibian shot ahead, and soon attained a velocity equal to that of the estimated rate of the gale, while, swooping through the thick bank of clouds, she hovered a good two hundred feet above the sea.

Meanwhile the inventor had thrust back a long sliding panel, disclosing a large square of plate glass.

"Don't be afraid to tread on it," he remarked. "It's tested to 400 lb. to the square inch. By the way, would you mind touching that switch?"

Holmsby did so, and instantly a brilliant searchlight beam was directed vertically from the underbody of the Amphibian.

For a few seconds only it swept the surface of the storm-tossed sea, illuminating the foaming breakers and the flying spindrift with silvery light. Suddenly Holmsby gave a warning cry:

"There she is."

With her decks almost hidden by a smother of foam lay a small ketch. Her mainmast had gone by the board, and she was riding to the wreckage with comparative safety for the time being, although drifting rapidly towards the iron-bound coast. Her mizzen was still standing, a closely-reefed sail having been set to keep her head more to the wind, while aft were three men clad in oilskins and lifebelts, clinging with the strength of despair to the iron horse that crossed the deck abaft the battened fish-well. Lashed to the stump of the mainmast was a still-smoking tar-barrel, but the waves had already extinguished its warning glare.

This much Holmsby saw by the aid of a pair of night-glasses. Instinctively he wondered how the Amphibian could render aid to the unfortunate toilers of the deep. He looked round for O'Rourke, but the Calderian had gone.

Presently he returned, having roused the sleeping crew.

"We are all ready, Mr. Holmsby," he exclaimed. "You are used to this kind of thing"—and he held up a megaphone. "Give them a hail to tell them to stand by for a rope."

As he spoke Don Miguel unfastened a dead-light in the floor of the compartment and slightly to the side of the glass panel. A perfect whirlwind, the first audible intimation of the strength of the wind, screamed through the aperture.

"Ahoy, there. Stand by for a rope!" shouted Reginald in stentorian tones.

"They can't hear us; we'll forge ahead to windward," bawled O'Rourke. "Now, try again."

This time the hail was successful. One of the men raised his arm, and proceeded to make his way for'ard, followed by one of his companions.

Then from the afterpart of the Amphibian a barrico, to which was attached a stout grass hawser, was paid out, till it trailed to lee'ard of the disabled craft.

Skilfully manoeuvred the airship forged ahead once more till the rope dragged across the stranger's foredeck. Once more the oil-skinned figure raised his hand, while, with a succession of blows with an axe, his mate cut away the raffle of cordage that held the floating gear.

With a jerk that well-nigh capsized Holmsby as he knelt at the open dead-eye, the Amphibian took the strain of the tow.

"Don't be alarmed," exclaimed Don Miguel, who had regained the lowermost compartment. "She'll stand it all right: this is not your Mayfly."

Reginald shut his jaws tightly at these words, but the Calderian was not slow to notice his guest's umbrage.

"Forgive me," he exclaimed; "I meant no offence. It was merely to give you confidence. A thousand pardons for my ill-placed remark."

"Don't mention it," replied Reginald unhesitatingly. "But where do you propose taking them to? I thought you meant to sling them aboard on a bowline."

"It would have meant a tedious delay ere the weather moderates sufficiently to land them," said O'Rourke. "I would only do that as a last resource. No, my plan is to tow the craft into St. Ives Harbour."

"It's dead to lee'ard, and there's a heavy breaking sea between the harbour piers," exclaimed Holmsby. "I know the place. Besides, with this wind the Amphibian would travel at such a speed that even if the ketch escaped being swamped she would carry too much way and smash herself to pieces ashore."

"You're right," assented Don Miguel. "But what alternative can you propose?"

"If you could spare a barrel of lubricating oil," replied Holmsby, "we could veer the craft in——"

"Excellent," exclaimed the Calderian warmly. "Your resourcefulness is remarkable."

Still forging ahead the Amphibian reduced her speed till the force of the wind drove both her and the towed vessel rapidly to lee'ard, the strain on the hawser being just sufficient to keep the ketch's head to the breaking seas.

Now through the mirk the red sector of St. Ives light appeared to view, while on either side the breakers thrashed themselves upon the rocks in a smother of milk-white foam.

"Port your helm slightly, sir," cautioned Holmsby. "That's better. Now the light shows white. It's straight in now."

Apprehensively the men on board the ketch cast their eyes towards the smother of foam that lay betwixt them and safety. They knew the danger.

The upper search-light, which hitherto had been unused during the act of rescue, was now switched on, and its beam directed upon the massive stone pier that now lay dead to lee'ard. In spite of the clouds of spray that from time to time completely hid it, the structure was black with people, sheltering under the lee of its protecting wall, for the lifeboat had already gone on an errand of mercy, a large brigantine having grounded on Hayle Sands.

Meanwhile O'Rourke had ordered a barrel of oil to be brought from the storeroom and placed on the lowermost floor close to the still-open dead-light. With a swinging blow of his axe one of the seamen stove in its head and, tilting the cask, allowed the oil to fall in a steady stream through the aperture.

In a very short space of time the oil spread over the water, beating down the spiteful crests in a marvellous fashion, so that the rescued craft, instead of being swept from end to end, now pitched sluggishly in the unbroken waves.

Still slowly backing, the Amphibian allowed the disabled ketch to be veered right between the harbour lights. Ropes were flung from the lee of the outer pier, and, amid the hearty cheers of the crowd, the almost exhausted crew were helped ashore.

Meanwhile the Amphibian, held by the hawser, was battling manfully against the gale. Yet, in spite of Don Miguel's most careful helmsmanship, the huge bulk was slowly yet surely beginning to slew broadside on. Once the wind caught her thus, her immense lateral structure would be swept landwards encumbered as she was by the heavy grass rope.

"Cast off the hawser, you idiots!" yelled Holmsby through the megaphone; but either his words failed to carry or else the people on shore would not slip the rope from the bitts.

"We'll be broadside on in a moment," exclaimed O'Rourke excitedly. "If we do, there'll be some damage done; but not to the Amphibian. Give them another hail, Holmsby."

Again Reginald shouted, all to no purpose. The Amphibian's bows were ten points off the wind.

Don Miguel gave a hurried order to his lieutenant. The officer rushed off and inserted another helia cylinder into one of the spare ballonettes. Then, as the huge vessel rose still higher in the air, a vicious squall took her on the port bow.

In a moment she literally scudded over the pier-head. There was a wild stampede on the part of the spectators to escape being capsized by the bight of the hawser—men falling over each other in all directions.

Then as the rope began once more to tauten the bight got foul of the lighthouse at the pier-head. The stone structure stood the strain, but as the rope ran up the column, the lantern was swept away. For a brief instant there was a heavy jerk as the whole bulk of the Amphibian told upon the hawser. Something had to go—and something went.

Like pieces of matchwood the oaken bitts of the rescued ketch were torn away from the deck, and freed from any restraining influence the Amphibian bounded upwards for a distance of nearly a thousand feet and, ere she could be brought head to wind, had drifted far beyond the little town.

"Great Scott! that was a holy smash," ejaculated Dick. "The lighthouse knocked clean out of action."

"It was not our fault," remarked Don Miguel "We gave them fair warning. I could, of course, have slipped the hawser; but since it is the only one of that length and size we have on board I was not going to lose it."

Just then one of the crew approached, saluted, and in a low, excited tone spoke a few words to his superior. Holmsby caught the words "aqua" and "merma."

"Something's sprung a leak, Dick," he explained, after Don Miguel had hurried away. "It seems serious, I should think, judging by the expression on his face. If we're obliged to attempt a descent here, I won't give much for our chances, by Jove!"

CHAPTER XIII

AN EXCHANGE OF SHOTS

"We've had a somewhat unfortunate mishap, gentlemen," announced Don Miguel on rejoining his guests. "Somehow or the other our main freshwater tank has started, and its contents have escaped into the limbers of the submarine. Consequently, since it is not clear enough to pump back, we must repair the tank and wait till the weather moderates before we refill and resume our voyage. I thought of bringing up over the Scilly Isles."

"I believe fresh water is scarce there," said Holmsby.

"Where, then, could we replenish the tank?"

"There's a good supply in the hills above the village of Zennor," said Tresillian. "I know the place well. We would also be fairly protected from the wind, if it remained in this quarter, and there is little chance of being seen."

"I do not mind publicity now," replied Don Miguel. "Nevertheless your proposal seems good. We'll wait till daybreak and see where we are."

Accordingly the aerial propeller was run at sufficient speed to counteract the drift caused by the force of the wind, and having given Don Carlos, his lieutenant, instructions as to course and altitude to be kept, Don Miguel and his guests retired to the officers' quarters.

Just before sunrise Holmsby awoke. His companions were still sleeping soundly, so, without disturbing them, he dressed and made his way to the lower storey.

The sliding panel still remained open, allowing a wide view of the country beneath to be made through the plate-glass window.

The Amphibian was going ahead very slowly. Possibly the gale had moderated, but it certainly had changed slightly in direction, for, instead of floating over the northern coast of the "toe" of the duchy, the airship was immediately over the town of Penzance.

Holmsby could discern the outlines of the coast with the utmost ease, the range of vision at an altitude of 1500 feet, embracing the whole of Mount's Bay, including St. Michael's Mount and the villages of Newlyn and Mousehole, while the rocks and submerged shoals of the bay were visible with startling clearness against the pale green sea.

So rapt was his attention at the unfamiliar sight of a familiar coast that Reginald was unaware that O'Rourke was standing behind him.

"Admiring the English Bay of Naples, Mr. Holmsby?" he asked, with his customary affability.

"It's stunning, sir; but haven't we got a bit out of our course?"

"Nothing to speak of. Don Carlos carried out his orders faithfully, but the wind veered slightly in the night."

"The Amphibian will cause a little excitement to the inhabitants of Penzance, I fancy."

"It's early yet; but no doubt some of the crews of the fishing smacks yonder have observed us. Seamen, as you know, use their eyes: it's part of their education. But I'm willing to wager that I would bring the Amphibian over an inland town and descend to within five hundred feet, without attracting attention, though, mark you, once one individual saw us the news would spread like wildfire, and the whole town would soon be gazing upwards with eyes and mouth agape."

"But the gale is moderating fast. We will drop to lee'ard a little and come up head to wind under the shelter of Land's End."

By the time the early breakfast had been done justice to, the Amphibian was over the village of St. Buryan. As Don Miguel had said, the wind was piping down, but its velocity was still too great to warrant a descent.

"If I were the commander of a fleet of hostile airships operating against your country that building would be one of the first I would destroy," observed O'Rourke, pointing to a house snugly sheltered betwixt two rocky headlands.

"The submarine and wireless telegraphy station of Porthcurnow—however did you know that?" asked Tresillian.

"You English are apt to despise the poor foreigner—it's a common failing with you, I fear," replied Don Miguel. "But the average foreigner—especially if he be a seaman—knows far more about your country and its defences than ninety-nine per cent. of its inhabitants. I once met the skipper of a German trader, who boasted, not without cause, that he knew the position of every fort between Aberdeen and Falmouth, and that even if the buoys were removed, he could navigate a vessel into every harbour on the south or east coast of Great Britain. Yes, gentlemen, the destruction of that place would mean that submarine communication with South Western Europe and Madeira would be almost impossible: the only working line remaining being that between Falmouth and Bilboa—and Porthcurnow is absolutely without means of defence. Well, you must excuse me, for I have to do the rounds: I think that is what you naval men term it."

O'Rourke had not been absent many minutes ere he returned.

"I've just been speaking with my London agent," he exclaimed. "He tells me there's a fine dust up about you. The authorities received your message, but seem to have regarded it as a hoax. More, there has been a serious shooting affair at Sampson's Down, and a troop of cavalry has been sent there from Exeter. No further details are obtainable at present. Madre! I wish I could get hold of a newspaper," he added tentatively.

"The London papers do not reach Penzance till late in the forenoon," said Dick. "Perhaps we might be able to get one, but at the present moment I don't know how."

"If you don't mind, I think you would be the best man to get one," said the ex-President. "There's not much wind under this hill. I'll bring the Amphibian as close to the ground as I dare and lower you by a rope. Take one of the gravity-neutralisers with you for your return, in case we have to ascend, but it's not advisable to use it for the descent. We will await you here."

"I'll do it," replied Dick resolutely. "But I think I know of a better plan. I'll walk into Penzance, get the papers, and take train to St. Ives. In the meantime you can take the Amphibian to Zennor Hill and carry on with the watering. It's a fairly short distance from St. Ives to Zennor, and I'll be back before four o'clock."

"You might take letters for us," added Reginald. "It would be a good plan to confirm our previous messages."

"You'll return to us, I hope?" said Don Miguel. "Nay, pardon me, regard my remark as unsaid."

"I'll return sure enough," replied Dick. "Am I the man to break his word or desert his comrade?"

Accordingly the Amphibian was brought within twenty feet of the ground above a gently-sloping field. Tresillian, with the uncharged neutraliser slung on his back glided down the rope and reached the earth in safety; then, with a reassuring wave of his hand, he started to walk rapidly in the direction of Penzance.

An hour later the wind had subsided sufficiently for the Amphibian to risk a descent. At an elevation of less than a thousand feet, she headed rapidly northwards towards the rugged hill that Tresillian had pointed out.

As the huge airship passed over the main road to Land's End, Don Miguel called Holmsby's attention to a couple of motor coaches lumbering along towards the Mecca of Cornish tourists—the most westerly point of England. Through his glasses the sub-lieutenant watched the holiday-making freight, but, sure enough, though out for sight-seeing not one of the occupants of the coaches chanced to look aloft at the greatest marvel of the twentieth century that was gliding serenely over their heads.

On arriving at the chosen anchorage the Amphibian manoeuvred until the copious stream was found, then, dropping her bow grapnel, shut off the motors and swung head to wind. For nearly a hundred yards the grapnel found no grip in the sun-baked turf, till, engaging in the top stone of a weather-worn cromlech, it allowed the huge vessel to ride motionless in the now almost still air. Then, with a barely perceptible jar, the Amphibian sank gently to earth.

Meanwhile the crew had been actively engaged in repairing the leak in the water-tank, and ere the landing operations were effected the work was completed. Four or five short lengths of hose were coupled up, a powerful centrifugal pump was set to work, and the fresh sparkling liquid flowed rapidly into the tank.

In less than half an hour the Amphibian was ready for her ocean passage. All that was to be done was to wait patiently for Dick Tresillian's return.

Holmsby and his host had taken the opportunity of "stretching their legs ashore," but on the completion of the tank-filling operations they boarded the Amphibian and took up their position on the promenade deck, where, by reason of the height of the aircraft, they were able to command a long stretch of the granite road that wended its way down Zennor Hill in the direction of St. Ives.

It was now nearly four o'clock, but still no signs of Dick Tresillian. Presently a motor-car was to be seen breasting the spur of the hill. When as close to the Amphibian as it could possibly be without leaving the road the car stopped and its three occupants regarded the huge craft with apparent curiosity.

After waiting for five minutes the car was set in motion, and was soon lost to sight in a dip in the road.

"Still no sign of your friend, Mr. Holmsby," remarked O'Rourke, after carefully scanning the distant highway through his field-glasses. "I trust that he has not met with a mishap."

"Perhaps there was not a convenient train or——" Reginald's words were interrupted by the zipp of a bullet whistling past his ear, while, with the sound of a sharp report, a volley of shots struck the bulky target presented by the Amphibian. Some of the missiles passed from one side to the other of the outer envelope, others cutting their way almost without resistance through the duralium skin flattened themselves against the proof metal sheathing of the submarine.

"Lie down!" shouted Holmsby to his companion, and instantly Don Miguel complied, calling at the same time for the rifles to be served out.

Through the hatchway swarmed the lithe Calderian crew, each man with a Jansen automatic rifle. Though they lacked the calm deliberation of the British seaman the men were not deficient in courage. Taking advantage of the scanty cover afforded by the turned-up edges of the deck, they began a rapid fire upon their practically invisible enemies, their bullets cutting up the turf all around a natural embankment behind which Holmsby had detected the movement of a man's cap.

Realising that the more they fired the better able were they to keep down the fusillade from their unseen foes, the crew shot rapidly and well. As for their assailants they had hoped to take the airship by surprise, send in several destructive shots, and get clear away in their car ere the Amphibian could reply; but so prompt were the crew that their treacherous attackers were literally trapped since they could not retire without offering a tempting mark as they drew clear of the sheltering bank of earth.

"Who are these fellows, I wonder?" asked Don Miguel of Holmsby, who had taken up a rifle and was joining in the firing. "Some of your Government friends?"

"No," replied Reginald. "Otherwise I would not be using this rifle. Unless I'm very much mistaken they are our old acquaintances of St. Piran's Round with motor-car F.O. 445."

"Hello!" he exclaimed after a pause. "There's Dick coming along the road. Now what's to be done? He'll be trapped to a dead cert."

CHAPTER XIV

DICK TRESILLIAN'S ESCAPE

There was no time to be lost. Ordering four of the seamen to follow him, Don Miguel went below. In a few moments the bow rope was paid out sufficiently to enable the stern grapnel to be broken out and hauled on board; then, as the Amphibian rose twenty feet in the air, the air-propeller began to revolve, and the gigantic vessel forged slowly ahead, the fusillade being maintained almost as lustily as of yore.

The care which Don Miguel had taken by securing the bow anchor in the cromlech now proved a source of difficulty, but, after a considerable amount of manoeuvring, the refractory instrument was shaken clear and secured to the bow of the vessel.

Thanks to the ingenious composition of the fabric of the outer envelope, the small-bore pistol-shots from the attacking party did but little harm, the punctures closing automatically with but little escape of helia. Nevertheless O'Rourke took the opportunity of inserting a charge into the seventh ballonette.

"Now we'll punish the rascals," he exclaimed, as the Amphibian soared aloft and the men on deck now, being in no position to use their rifles, descended to the lowermost compartment whence they could continue their fire with good effect. "I'll fly right over their heads, and I'll simply wipe them out."

Seeing their danger the three assailants broke cover and ran towards the motor-car. One of them fell and lay writhing on the grass, but the others, heedless and regardless of their companion's fate, gained their desired refuge.

Now the shots from the Amphibian rained thick and fast upon the car, but the occupants had already provided for their personal safety. An armoured hood had been drawn over the vehicle, successfully stopping the bullets in spite of their high velocity and powers of penetration.

Then as the Amphibian headed towards the spot where Dick, scenting danger, had stopped, the F.O. 445 started in pursuit, jolting over the rough grass-grown down, one of the occupants using his automatic pistol while the other steered.

Seeing the airship coming in his direction, and the car bumping along in its wake, Dick realised that something was amiss, especially as, for the first time, he heard the noise of the firing.

Knowing that it would be impossible to charge the gravity-neutraliser while it was fastened to his back, Tresillian did the only thing possible. He strapped it across his chest, inserted the charge, and waited, wondering what would happen if he miscalculated the speed of the Amphibian and jumped wide.

"Stand by!" shouted Holmsby, who had once more taken up his station on the promenade-deck. "Now!"

The bow of the Amphibian was nearly fifty feet in a diagonal distance from the waiting man: the car but a hundred yards off. Unhesitatingly Dick bent his knees and leapt.

Fortunately for him the occupants of the spurious F.O. 445 were somewhat astounded at the apparently supernatural appearance of a man leaping ten times his own length in air; but, quickly recovering from his surprise, the man with the pistol, having just recharged the magazine, let fly as fast as the automatic mechanism would permit.

"Good heavens!" muttered Holmsby. "If a single shot should pierce the neutraliser."

Strange as it may appear, he never gave one thought to the fact that one of the stream of bullets might hit his comrade in some vital part: he only contemplated the possibility of a fearful fall to earth should the supporting medium be damaged.

Up shot Dick, sprawling on his back as it were, with arms outstretched, for the lifting apparatus, being designed for the wearer's back, now showed a tendency to capsize him.

Just as he reached the highest point of his flight, Don Miguel had the whirling air-propeller stopped, and, adroitly manoeuvring the Amphibian, brought her smartly underneath Tresillian's descending body. Ere Dick rebounded, Holmsby held him in his powerful grasp, safe and sound upon the deck.

With a swift rush the Amphibian shot a thousand feet skywards, presenting a target that it was almost impossible to hit.

"Now to have my revenge," exclaimed Don Miguel, and, bending over the hatchway, he gave orders for the bomb-dropping gear to be brought into action.

"Watch the effect of one missile—utter annihilation," he exclaimed.

"Excuse me, señor; you must not," said Reginald quietly.

"Must not?" replied the ex-President hotly. "Pray, why?"

"Look down," continued the sub-lieutenant. "The car has stopped close to that little village. Would you, in your desire to revenge yourself upon two worthless scoundrels, wipe out perhaps forty or fifty harmless people?"

For an instant the two men looked each other in the face—the cool Saxon and the impulsive Creole.

"You are right," replied Don Miguel, after a pause. "Nevertheless I'll have them in my power ere long."

"Ay," assented Holmsby. "You'll have them right enough—in due course. Even I am as anxious as you to settle old scores, but there is a time and place for all things."

Without another word O'Rourke went below, and in a few minutes the Amphibian turned till her bow pointed south-west. Then, with a whirr as her propeller ran at top speed, she cleft the air in the direction of the broad Atlantic.

The Englishmen endured the hurricane caused by the speed of the craft through the air as long as they could, then, going below, took up their position at the observation panel in the floor of the lower compartment.

"How did you feel when you were being shot at in mid-air, Dick?" asked Reginald, as the last outlying rocks of the Scilly Islands were left astern and nothing but an unbroken expanse of water was to be seen.

"A sort of a kind of a first of September partridge feeling," replied Tresillian all in one breath. "No more of that for me. The shots almost grazed my upturned nose."

"All's well that ends well," said Holmsby complacently. "But you brought the papers?"

"Yes, and read them. A pretty kettle of fish, I can assure you."

"Where are they?"

"O'Rourke has them, I believe."

"I don't think I'll trouble him just yet: he seems somewhat crusty. Tell me——"

"Mr. Holmsby!" came Don Miguel's voice from above.

"Ay, ay, sir," replied Reginald promptly, as he sprang up the ladder.

The commander of the Amphibian was standing in the conning-tower, grasping the steering-wheel. Seated on a bench by his side was Don Carlos, looking ghastly pale, and with his right hand swathed in bandages.

"I regret to have to inform you that my lieutenant has been badly wounded, Mr. Holmsby," began Don Miguel. "During the last exchange of shots a bullet severed two of his fingers. Without saying a word to anyone he continued to superintend the seamen under his orders, and it was not until we were fairly out to sea that he collapsed through loss of blood. I've rendered such surgical assistance as lies in my power, and can only trust that the natural healing will be a matter of time. But, meanwhile, Don Carlos will be totally unfit for doing any work, so I ask you as a favour to take his place until his recovery."

The sub-lieutenant hesitated. Visions of the dire penalties threatened by the Foreign Enlistment Act, the Naval Discipline Act, and a score of other formidable Acts flashed across his mind.

"I know what you are thinking of," continued Don Miguel. "But you need not trouble on that score. Whether you take up arms against a friendly state or not depends entirely upon yourself. There is this knowledge, however," and the Calderian pointed to the two newspapers lying on the table. "Both you and your comrade are officially dead."

"What?" gasped Holmsby.

"Dead as my illustrious ancestor, Don Patrick O'Rourke, as far as the British Admiralty is concerned, I fancy. Read this."

Holmsby took the paper. Printed in bold headlines he read:

"STARTLING DEVELOPMENT IN THE CORNISH MYSTERY.—SUPPOSED MURDER OF TWO> ADMIRALTY OFFICIALS.—A NAVAL PENSIONER FOUND DANGEROUSLY WOUNDED.

"St. Ives. Tuesday noon.—Our special correspondent telegraphs that the mysterious events centring around Sampson's Cove have developed with startling rapidity. On Monday night two visitors to Penkerris, who, it appears, had been sent from the Intelligence Department of the Admiralty to make inquiries concerning the presence of a mysterious airship that had been seen in various parts of Cornwall, left the village with the supposed purpose of conducting their investigations. With them, apparently, was Lieutenant Haslar, R.N. (retired), whose intimate knowledge would prove of great assistance to the Admiralty officials.

"Failing to return on the following morning the services of a party of coastguards were requisitioned and a search made of the fenced-in portion of the ground. Lieutenant Haslar was discovered, dangerously wounded and insensible, outside the fence and close to the edge of the cliff. He was promptly removed to his house, and on the arrival of a doctor was found to have been shot with a small-bore bullet through the left lung. Up to the time of wiring he has not recovered consciousness, so that the events of the previous night must at present be left to conjecture.

"Presumably the three men were suddenly attacked, Mr. Haslar falling as he attempted to escape, while the other unfortunate investigators were hauled over the cliff.

"It is well known in the district that Lieutenant Haslar gave frequent warnings to the authorities of the danger to the community at large by the presence of a band of desperadoes with the most potent instruments of science at their command. Now the gallant officer has set the seal to his assertions, possibly at the cost of his life.

"We understand that cavalry are to be brought into the terrorised district, and in the meanwhile armed parties of coastguards are actively engaged in patrolling the cliffs in search of the missing officers and their assailants. The next few hours may produce startling developments."

"What do you think of that?" asked Don Miguel, when Reginald had finished reading.

"Absolute rot!" replied the sub. "Someone's on the wrong tack. But I'm sorry about old Haslar, even though he was a surly bear."

"Who's Haslar? I see his name mentioned once or twice. Did he accompany you?"

Holmsby hastened to explain that he and the pensioner were practically rivals.

"It's strange," he added. "We passed him going homewards as we made for Sampson's Down. He must have returned. I wonder who shot him: none of your men?"

"Most emphatically no," replied Don Miguel. "But here is another paper—the St. Ives Romancer."

"THE MYSTERIOUS AIRSHIP ATTACKS ST. IVES. WANTON DESTRUCTION OF THE LIGHTHOUSE.

"Late last evening, or rather in the early hours of the morning, the mysterious airship, which has recently been prominently brought before the notice of the public, showed herself in her true colours. During the height of the north-easterly gale that, as related elsewhere in our columns, wrought havoc on our coasts, the airship, manned by a crew of desperadoes, wantonly destroyed the lighthouse on the pier-head. By what means she succeeded in performing this wilful act of destruction—an undoubted outrage against all nations—remains a mystery. Many of the spectators avow that it was by the agency of an electric discharge. Fortunately the damage was confined to the lighthouse, the gale sweeping the sky-pirate over the town ere she had time to continue her deeds of inexplicable destruction."

"More bungling. That editor ought to be made to swallow his confounded paper," said Holmsby savagely. "Here, Dick, come and see the account of your premature decease."

"I've already done so," replied Tresillian, as he rejoined his companion. "Dulce et decorum est pro patria mori. But, seriously, Rex, who could have winged old Haslar?"

"Give it up; unless it were our old friends F.O. 445. There's one consolation: our letters will reach the Admiralty to-night, and will help to clear up several false impressions."

Dick's face suddenly paled as he clapped his hand to his breast-pocket.

"I'm a regular ass!" he exclaimed. "I've forgotten to post them. What's going to happen now?"

"That remains to be seen, as the ship's cat said when it upset the ink over the commander's log-book," replied Holmsby. "At any rate we are both officially dead, and there is a vacancy in the Active branch of the King's Navy to say nothing of one in the hard-working Civil Service."

"Then I would suggest that present complications are considerably simplified, Mr. Holmsby," remarked Don Miguel. "Until you are resurrected you have no official status: your very existence is denied. Therefore, it seems to me, there is no reason why you should not accept my offer and become lieutenant of the Amphibian for the time being."

"May as well go the whole hog," replied Holmsby, with forced cheerfulness. "I'll accept, subject to one condition."

"And that——?"

"That should the Amphibian become embroiled in a conflict with any nation, except with the rebels of Calderia, we can claim the right to be set ashore or on board any craft we may happen to fall in with."

"Agreed!" exclaimed Don Miguel O'Rourke, extending his right hand.

CHAPTER XV

THE TALPICAN AEROPLANES

Swiftly the Amphibian sped on her course towards the distant Calderian shores, and once clear of the recognised trade routes hour after hour passed without sign of a vessel upon the vast expanse of ocean.

On the evening of the second day after leaving the Cornish coast the airship passed beyond the range of her wireless telephone, and from that time until her arrival off the port of Nalcuanho all communication with the outside world was practically impossible.

Early on the morning of the third day the Bermudas hove in sight, and flying at an altitude of nearly 2000 metres, the Amphibian passed directly over the town of Hamilton, unnoticed by any of the inhabitants.

The same evening she flew high over Moro Castle and the town of Havanna. Don Miguel gave orders for the lower search-light to be switched on, and instantly the town was swept by a dazzling ray of light.

By the aid of their glasses the Englishmen could see the Plaza crowded with Creoles and negroes taking their evening promenade. At the first flash, falling apparently from the sky, shouts of terror rose from the superstitious Cubans. Some fell prostrate on the ground, others ran shrieking to the shelter of the narrow streets, and in a few seconds the Plaza was deserted.

"If that had been the Talpican army we would have gained a splendid moral victory," exclaimed Tresillian.

"Unless I'm much mistaken the Talpicans are made of sterner stuff," replied Don Miguel. "We will not be able to clear them off Calderian territory without bloodshed, I fancy. Now, gentlemen, it is about time the watch is set, and those off duty take their rest. This will be the last opportunity of undisturbed repose for some days to come."

At sunrise Holmsby was out upon the promenade-deck, marine-glasses in hand. Away to the south-west there appeared to be an irregular crimson cloud. It was the snowclad peaks of the Calderian Sierras tinged with the glow of the rising sun.

"Quite seventy miles off, I reckon," commented Reginald. "Another half-hour and we'll be on the scene of hostilities."

The crew of the Amphibian were already busily engaged in clearing for action. Speed was reduced while the two 0.755 centimetre quick-firers were brought from below and mounted on the promenade-deck. Racks of sinister-looking polished shells were ranged alongside the guns and secured by strong lashings; while amidships a Maxim was mounted on a light tripod and placed in such a position that it could command a wide arc of fire on either broad-side.

Just before eight o'clock Don Miguel O'Rourke, now attired in a gorgeous gilt-braided uniform, came on deck, and as eight bells struck the Calderian ensign was run up to a small staff abaft the promenade-deck.

Then, with the flag blowing out as stiff as a board, the Amphibian resumed her greatest pace direct for the city of Nalcuanho, now barely twelve miles distant.

"By Jove, señor, I believe we are too late," exclaimed Holmsby, as the two stood at the for'ard scuttles of the conning-tower. "The place is already in flames."

Such evidently was the case, for in the almost calm air a thick column of flame-tinged smoke soared skyward.

"We are not too late for revenge, Mr. Holmsby," replied the ex-President.

"Revenge," thought Reginald. "This fellow seems to think of nothing else. All his power, riches, intellect seem to exist for that one purpose."

"They are still firing," exclaimed Don Miguel. "See, there are shells bursting away to seaward."

"Yes, and do you see what they are firing at?" asked Holmsby quietly. "See those little black dots, like a swarm of flies, flopping up and down?"

"Caramba!" muttered the Calderian. "They are aeroplanes."

"Talpico has evidently made strides in the science of warfare since you left Nalcuanho, señor," remarked Reginald. "However, we must be careful. What do you propose to do?"

"Stand on and see what happens. I hope they'll turn tail when they see the Calderian ensign floating in the air. See that the men at the quick-firers have the correct range, Mr. Holmsby."

But ere Reginald could leave the conning-tower, Don Miguel shouted to him to return.

The Englishman was surprised at the change in the Calderian's features. The deep olive tint had given place to the sickly yellow of terror. In the hour of peril the vaunted rescuer of his country completely lost his head.

"What must we do, señor?" he gasped, pointing to the Talpican aeroplanes, which, having formed into two long lines en échelon, were advancing straight for the Amphibian.

"Do?" replied Holmsby, almost roughly, for the sight of the craven ex-President provoked his deepest resentment. "Do? Why, act, man, act!"

"I cannot."

"Shall I, then?"

Don Miguel gave a feeble gesture of assent. Reginald immediately sprang to the wheel, put the tiller hard over, elevated the planes to their highest capacity, and shouted to the engineer to charge the four remaining ballonettes.

"Look sharp, Dick," he shouted. "Serve out the neutralisers. We'll rise till we drop those fellows—or bust in the attempt."

Like an arrow from a bow the Amphibian darted upwards, just missing a rocket from the nearest aeroplane of the starboard division, the hissing missile of destruction passing a few feet below the envelope. Had the rocket engaged it would have burst a hole through the duralium with the greatest ease in spite of the asbestos sheeting for, by an ingenious mechanical device, the heads of these newly-invented anti-airship weapons were provided with a sharp rotary drill. The impact would be sufficient to enable the point to obtain a grip, and its spiral action would speedily enlarge the aperture, through which the unquenchable flame of mingled petrol and sulphur would pass, causing the total destruction of the best-protected aircraft in existence.

"Ugh, you brute!" ejaculated Holmsby, who alone had noted the Amphibian's narrow escape.

It seemed as if the whole fleet of aeroplanes were falling seawards, so swift had been the airship's vertical leap. In less than half a minute the hostile fleet looked no bigger than a covey of partridges, as, superbly managed, they circled in ever-ascending spiral curves in fruitless pursuit of the Calderian airship.

Suddenly, and without orders, one of the crew released a bomb from the lowermost deck. The gunner evidently knew his work, for, in setting the fuse to explode at 5000 metres, he gauged the distance to a nicety.

With a roar that was greatly intensified by the rarefied atmosphere the highly-charged missile exploded in the midst of the pursuing aeroplanes.

Holmsby, in the conning-tower, was in ignorance of what had occurred; but Tresillian had run to the floor-panel and saw the tragedy enacted.

The blinding flash was instantly concealed by a thick yellow cloud mingled with fragments of the annihilated machines. Some, beyond the actual zone of explosion, were capsized by the blast of displaced air, their occupants falling to a quick yet horrible death; others had their planes burnt and rent by the spurting flames, and like flies shorn of their wings plunged swiftly downwards; while four only, rocking violently in their endeavour to counteract the air-eddies, succeeded in recovering their balance. Terror-stricken, their occupants executed a terrific vol-plané till they almost reached the surface of the sea, whence they fled for safety to the lines of the Talpican army.

"What's wrong with Don Miguel?" asked Dick, as he joined his comrade in the conning-tower with the news of the appalling disaster to the pursuers.

"Blue funk!" whispered Reginald.

"I don't wonder at it: I feel as sick as a dog after seeing that," and Dick made a downward motion with his hand. "If that's war I want to see no more of it."

"Our friend yonder had his attack before the scrap began," said Holmsby, contemptuously glancing in the direction of Don Miguel who still remained huddled up on the floor. "Just fancy, Dick, I'm in command of this caboodle now. Here we are at 4000 metres above the sea-level, and in danger of the envelope bursting at any moment. I wonder what old Pennington would say if he could see me now?"

"Don't stop to think, old chap; but for goodness' sake let's descend a few miles. See, already there is ice forming on the turtle-back deck."

Realising the urgent necessity of following Tresillian's advice, Holmsby ordered the engineer to release the helia from the four now-superfluous ballonettes.

The man instantly grasped one of the levers actuating the valves; but though he used considerable force the steel rod remained immovable. The others he tried with the same result.

"Pardiez, señor, I cannot open the valves," he gasped. "They are frozen."

Holmsby glanced at the aneroid. The Amphibian was still rising. Would the envelope withstand the terrific internal pressure?

CHAPTER XVI

A SWOOP FROM THE SKY

"Señor O'Rourke!"

Bending over the almost motionless body of the terrified inventor, Holmsby called him by name. There was no response.

"He ought to be made to rouse himself, Rex," said Tresillian. "Hang it all, man; it's his invention, isn't it? Why can't he be made to control it? Shake him."

Thus adjured, Holmsby turned Don Miguel over on his back. The man's eyes were wide open, his teeth chattering like castanets, his face absolutely devoid of colour.

"Come on, get up and play the man!" shouted the sub. "We're in a bit of a hole. Don't be afraid—the aeroplanes are smashed to a jelly."

The Calderian gave no sign of intelligence. He lay, breathing heavily, yet apparently devoid of all his senses.

Drawing his revolver from his hip pocket, Reginald held it to O'Rourke's temple.

"Get up, you white-livered scoundrel," he said sternly, "or, by Jove, I'll——"

The sub. paused to note the effect of the threat; but his action and words were wasted. Don Miguel was temporarily dead to the world.

"Confound the fellow," he grunted. "We must leave him alone: he's properly off his head. Here, Dick, give me a hand with this lever. Ah! That's good."

By their united efforts the Englishmen succeeded in reversing the elevating planes, but the helia release-valves obstinately refused to move.

"Now we'll try the motor and see if we can descend in spite of the lifting power of the ballonettes," exclaimed Reginald. "Perhaps we may succeed in striking a warmer zone of air and thus melt the ice."

Cautiously running the motor at half speed, since he feared that the vibration might complete the anticipated rending of the envelope, Holmsby noticed with intense satisfaction that the Amphibian was beginning to gather way and descend obliquely; but in a few moments the huge fabric began to tilt so steeply that the sub-lieutenant had to re-trim the planes to prevent the craft from assuming a vertical position.

"Now what's to be done, Dick?" he asked. "It's evident that she won't descend in a proper manner. If she tilts too much I'm afraid the motor will be wrenched from its bearers or some of the heavy gear will be started. Look, it's 4900 metres now."

"Couldn't we hack one of the ballonettes through from the outside?"

"Impossible, I'm afraid, Dick. The men had to take shelter below by reason of the intense cold when we were at only 3000 metres. They could scarcely breathe."

"We'll both have another shot at the valves. Something is bound to go if we heave for all we're worth."

"All right—but one moment: are all the neutralisers served out and charged?"

"Served out, but not charged."

"Then I'll give the order for that to be done. If the ship gets out of control and makes a downward plunge it may be possible to save our lives before she plunges into the sea. She may fall gently or she may go with a terrific smash—it all depends on how the ballonettes stand it."

In a few minutes the crew were ready for the unhoped-for emergency, Holmsby and his comrade having likewise provided for the expected catastrophe.

"By Jove, Rex!" exclaimed Tresillian, as they made their way towards the valve-levers, "I don't think this apparatus has the same buoyancy as it had before."

"I'm certain of it," replied Holmsby. "It is doubtless due to the rarefied condition of the atmosphere. If we leapt overboard it's a moral certainty we should fall like a stone for a few miles till we entered a stratum of normal density. By that time we would not be worth much, I fear."

"Then how is it that the helia in the Amphibian's ballonettes has a comparatively greater lifting power?"

"It hasn't—bulk for bulk. That's what I'm afraid of. If we cannot open those valves the helia which is sufficient to support the Amphibian in a rarefied atmosphere will assuredly burst the envelope in denser air. Already the interior pressure is about as much as the fabric will stand. So the sooner we start the valves the better. Now, all together."

Desperately the Englishmen tugged at one of the refractory levers, but all to no purpose. The steel rod bent to almost a semicircle, but the actuating rod remained fixed as if an immovable part of the airship's frame. The effort well-nigh left the two men breathless; the thinness of the air rendered breathing a matter of difficulty, and for some minutes they could only sit down, gasping for breath while beads of perspiration froze on their foreheads.

"Try the motor once more," at length suggested Dick. "Tell the engineer to run half speed astern and see if the Amphibian will keep her balance better that way."

But after several attempts to start the engine the engineer made the startling discovery that the petrol had become frozen. Holmsby looked at the thermometer. Even within the confined space of the conning-tower it registered -15° centigrade.

"How long will it be before the natural leakage of the helia will be sufficient to cause the Amphibian to descend?" asked Tresillian.

"Goodness only knows. Don Miguel might, but—well, look at the man."

"Then we are like Mahomet's tomb—floating betwixt heaven and earth—until something happens to——"

A vicious hiss—the sound of escaping helia interrupted Dick's words. The next instant officers and crew were flung violently against the forward bulkheads of the compartments.

One of the after ballonettes had burst, fracturing four others. Instantly the Amphibian, her buoyancy being contained in the five 'midship and for'ard helia-chambers, tilted nose upwards, and began to fall swiftly towards the dark blue expanse five miles beneath her—to wit, Mother Earth.

Helplessly the despairing men held on to whatever came nearest to their hands. Even had they retained their presence of mind and attempted to leap from the falling aircraft, the rush of air past the conning-tower hatch prevented it from being opened. From intense cold the temperature, suddenly raised by reason of the friction of the air, changed to extreme heat. The blades of the huge for'ard propeller were compressed against the curve of the Amphibian's bow as she plunged to an apparently unavoidable fate upon the soil of Calderi.

Even in this moment of peril, Holmsby kept his eyes upon the clock and the barometer. In one minute and a half the mercury had risen over twenty-three inches, representing a fall of four miles, at a mean rate of 160 miles an hour.

Then it was that Holmsby became aware that the awful velocity was being retarded. The buoyancy of the still undamaged ballonettes was sufficient to break the final plunge.

With newborn hope he reached up to the elevating levers. Thank heaven they were still in order. Scarcely daring to hope, he gently deflected the two nominally horizontal rudders. The Amphibian made a decided movement towards regaining her normal position of equilibrium; but the unequal balance of the buoyancy chambers still gave her an oblique inclination of her major axis. Still that was enough to break her fall.

"Dick!" shouted the sub.

There was no reply. Tresillian was lying by the side of the craven Don Miguel. The strain had been too much for him: he had swooned.

"Look alive, men!" shouted Holmsby in Spanish, but of the crew only two showed signs of intelligent movement and came crawling through the narrow hatchway betwixt the conning-tower flat and the 'midship compartment. Instinctively they pinned their hopes on the coolness of the young English officer.

One glance through the for'ard scuttle showed Holmsby that the Amphibian was not now in danger of falling upon hard ground. Could her present oblique course be maintained she would strike the water some distance outside Nalcuanho Harbour.

"Secure that hatch!" continued Reginald, pointing to the only means of egress which, though closed, was not held firmly in position by its locking-levers. Then having satisfied himself on this point, Holmsby kept his attention upon the disabled airship's course.

Now, but eight hundred yards beneath the falling Amphibian, he could see the six battleships and cruisers of the Talpican navy steaming in single line ahead, with a dozen destroyers spread out on their seaward side. The fleet had been engaging the Calderian batteries, but on discovering the crippled Amphibian they had ceased firing to see the result of a headlong plunge from the sky.

To Holmsby it seemed as if nothing could prevent the Amphibian from falling athwart one of the hostile craft, but in a few minutes the ever-decreasing distance showed that there was room and to spare betwixt the ships should the direction of the diagonal flight be kept under control.

Fortunately the Talpican fleet did not possess quick-firers mounted so as to enable them to repel the aircraft, their extreme elevation being not more than 45°; but, recovering from their surprise, the crew of the Puebla, the leading ship of the line, prepared to hazard a broadside from their secondary armament ere the hapless airship struck the surface of the sea.

Suddenly a gust of wind caught the falling craft, and instead of descending when Holmsby had hoped, the Amphibian swerved. For one brief instant it seemed as if she would descend upon the Libertad, the second ship in line.

Her crew had a momentary vision of the gigantic airship swooping down athwart her tapering masts; there was a series of crashes as the raffle of wireless gear came tumbling from aloft, a resounding splash like the blow of a whale's tail, and the Amphibian disappeared beneath the waves in a cauldron of boiling foam.

CHAPTER XVII

"WE HAVE STILL THE SUBMARINE"

The wreck of the Amphibian rested on the ocean bed eleven fathoms beneath the surface. The shock of the impact was not sufficient to deprive the gallant sub-lieutenant of his senses, and, keenly alert to the urgency of immediate action, he instantly rallied those of the crew who were capable of understanding and acting upon his orders.

"Close No. 4 starboard valve," shouted Holmsby, for under the terrific pressure water was hissing like escaping steam through the practically-closed apertures in the 'midship section of the submarine.

Fortunately, though Reginald was unaware of it, this leak had proved to be of inestimable service to the hapless Amphibian. It destroyed her slight reserve of buoyancy, otherwise the craft would have risen to the surface ere the crew could take steps to prevent her so doing, and thus prove an easy target for the guns of the Talpican squadron. As it was, the flow of water was checked just at the right time.

Having ascertained that the hull of the submarine was perfectly sound and watertight, Reginald turned his attention to his companions. Tresillian was his first care. The Cornishman lay perfectly motionless, the sudden change of temperature, combined with the confined air within the submarine craft tending to prolong his state of insensibility. His face was pale and pinched; his eyes dull; pulse almost imperceptible, and breathing very feeble, while Holmsby could scarcely detect any signs of respiration or circulation of the blood.

Placing his comrade's body in a horizontal position with his head slightly raised, Reginald bared his patient's neck and chest and proceeded to chafe his limbs. For nearly a quarter of an hour he persevered, leaving off only to administer an occasional teaspoonful of brandy—all apparently to no purpose.

"Try the oxygen, señor," suggested one of the seamen, who was engaged in trying to revive one of his comrades.

Holmsby made the experiment almost in fear and trembling. To him the use of the gas was like treading upon dangerous ground, but in the absence of the necessary fresh air, the course seemed the only possible one.

To his unbounded delight the experiment proved successful, and Dick opened his eyes.

"Where am I? Am I still alive?" he muttered fearfully.

"Alive, ay," replied Holmsby encouragingly, "and as safe as the Bank. Now lie still and don't ask any more questions for some time to come."

But Tresillian would not be quiet. Possibly the use of the oxygen hastened his recovery, for in less than a quarter of an hour from the time he opened his eyes, Dick was, to use his own words, "quite chirpy."

Meanwhile most of the Calderian crew had recovered from the effect of the terrible strain upon their nerves, for beyond a few slight contusions few had sustained injury. Don Carlos, the incapacitated lieutenant had, however, received a nasty gash across the forehead; for, having his hand bound up in splints, he had been unable to take a secure hold when the Amphibian began her earthward flight.

As for Don Miguel O'Rourke, he, too, had partially recovered from his attack of abject terror, and lay on the floor crying silently, ignorant and heedless of the circumstances of his surroundings.

"I say, Rex, old fellow," began Dick, as Holmsby returned from holding a consultation with the engineer, "where are we; and what has happened? Don't be afraid to tell me, for I feel as fit as a fiddle."

"We fell, Dick—-nearly crashed on top of one of the Talpican battleships. At present we are lying at the bottom of the sea in eleven fathoms of water."

"Lying en perdu till the enemy give us a chance to ascend, I suppose. Then we can try the effect of a few more bombs."

"Lying here because there's no help for it, Dick. The Amphibian belies her name. As an airship, her days, I fear, are over."

"But we have still the submarine."

"True; and what is more, I mean to let those Talpican rascals know it, if they give any more cause. They were not content with seeing the Amphibian fall helpless from the clouds, but they must needs prepare to hull her with their quick-firers at close range."

"Did they?"

"No, but it wasn't their fault that they didn't."

"How is Don Miguel faring?"

"Don't mention him," replied Holmsby contemptuously. "He may be a most clever inventor, but he has no physical courage. His nerve failed him at the moment when it was most required."

"So did mine, Rex."

"But you are differently situated. You did not boast of revenge; you did not aspire to taking this marvellous fighting machine into action: he did both, but when it came to the point—well, you saw what happened."

"What do you propose to do now?"

"Do? Why, carry out my promise to Don Miguel. Give him a fair chance to regain the presidency, support him as well as I can bring myself to do without losing my self-respect, and then, Dick, we'll make tracks for home."

"Is the Amphibian much damaged?"

"The envelope is, I fear; but the submarine part seems as sound as a bell. The motors, too, are in working order; at least, so the engineer informs me, but the aerial propeller is done for. If you feel equal to it, look through the conning-tower scuttles and see the extent of the damage."

"Of course I feel equal to it," replied Tresillian, but as he rose to his feet Holmsby noticed that he staggered more than once.

The glare of the bright tropical sunshine was sufficient to penetrate the water even to the depth at which the stricken craft had sunk. Peering through the thick plate glass, Tresillian could form some idea of the extent of the damage.

The Amphibian was lying on an almost even keel, with her bows somewhat depressed and with a slight list to starboard. For quite twenty feet the fore turtle-back deck had been rent, the duralium plating resembling the jagged edge of a saw. Beyond this cavity, through which the helia from the five injured ballonettes had forced its way, no other fracture of the envelope was visible. Only one blade of the aerial propeller remained, but that was so badly twisted that it would be useless even had the Amphibian been capable of supporting herself in the air. The remaining ballonettes were sound, but useless for lifting purposes until the balance of the craft had been restored by the repair of at least two of the for'ard ones.

It was indeed fortunate that the two members of the Calderian crew who had retained their senses had the presence of mind to open the valves of these compartments ere the Amphibian struck the water, otherwise the buoyant afterpart would have floated like a cork—an easy target to the guns of the Talpican fleet.

While the two Englishmen were looking through the scuttle, a polished cylinder, followed by a wake of eddying water and air-bubbles, flashed through the transparent sea barely twenty feet above the Amphibian.

"Heavens!" exclaimed Tresillian. "A torpedo. The beggars are trying to settle our hash. Luckily we are too deep down for a torpedo to strike us, even when run at its maximum depth of submersion. I hope they won't attempt to use electro-contact mines, though."

"How have they spotted us?"

"Probably they heaved a mark-buoy over the spot where we disappeared; or we may be visible from their mastheads. It's remarkable how deep one can see from aloft in tropical seas. All right, my beauties," he exclaimed, as he made his way to the hatchway communicating with the forepart of the submarine. "I'll teach you a lesson."

The Calderian crew, now recovered from the effects of their fright, were at their posts. In a few moments the bow torpedo tube was launched back and a deadly cigar-shaped missile placed in the tray. Holmsby's only fear was that the weapon in leaving the tube would strike the debris of the aerial propeller, for owing to the injuries it had received it was found impossible to withdraw the shafting and feather the remaining blade.

Meanwhile the principal centrifugal pumps were engaged in throwing out the water that had made its way into the submarine through the improperly-closed valve; and as soon as the huge metal cylinder began to grow "lively," Holmsby ordered the engineer to restart the motors.

He was now back in his place in the conning-tower, his right hand grasping the steering-wheel, his left on the lever controlling the horizontal planes, while his eyes were fixed upon the apparently unbroken expanse of semi-opaque water ahead. It mattered not to him whether the Amphibian was encumbered with a framework of useless plating, or whether she would never again soar in the air. His comrade's words rang in his ears: "We have still a submarine." A submarine? Yes, and, by Jove, he meant to make good use of her.

Slowly the Amphibian rose from her ocean bed, then, gathering way, crept over the bottom of the sea—so close to it that the wash of her following wave stirred up a long wake of sand-discoloured water.

By sheer good luck the submarine was heading straight for the battleship Libertad. From the forebridge her navigating-officer saw the tell-tale swirl, and, in a panic, signalled to the engine-room for full-speed ahead. A warning blast from the syren of the Paulo told him that his vessel was heading straight for her consort. There was not sufficient space to up or down helm. Full-speed astern! With the foam bubbling in cascades on either side of her quarter the Libertad slowed down, stopped, then began to gather stern-way.

Suddenly Holmsby, from his post in the conning-tower, caught sight of a dark, indistinct mass looming through the water. It was the Libertad. Now he could discern the swirl of her port-propeller as it strove to check the momentum of the forward motion of the ship.

Slightly elevating the bows of the Amphibian, Holmsby gave the order to fire, and with a sharp detonation, followed by a characteristic hiss, the torpedo left the tube. The range was short—almost too close for the rule-of-thumb "margin of safety," but, being without a periscope and not daring to rise till the top of the conning-tower was awash in order to take his bearings, the sub-lieutenant was compelled to take the risk.

At that distance a miss was almost an impossibility. Ere the Calderian engineer could obey Holmsby's order to reverse the submarine, the deadly missile struck the Talpican warship fairly amidships and about twelve feet below the armoured belt.

Instantly there was a tremendous explosion, followed by another equally terrific as the primary shock affected the warship's magazine with disastrous effect.

The concussion caused the sea to be violently agitated. Even the submerged Amphibian rolled like a stricken porpoise as she backed from the scene of her exploit.

The Libertad had been literally torn to pieces both above and below her armoured belt. Ere the fragments of metal had fallen from the immense height to which they had been hurled the shattered hull sank like a stone.

The result of the sharp stern lesson justified its application. Panic seized the surviving vessels of the Talpican squadron, and, steaming at full-speed ahead, their funnels belching out thick clouds of black smoke tinged with deep red flames, they headed for the doubtful security of Sta. Cruz Roads.

Reginald was perfectly satisfied with his victory. The Calderian coast had been freed from the presence of the powerful hostile fleet. Pursuit would have been useless, the Amphibian being, in her damaged condition, capable of doing a bare seven knots; but the terror of the mysterious vessel that had dropped apparently crippled from the clouds and yet retained the means of sending one of their finest battleships to the bottom was sufficient to totally demoralise the Talpican fleet.

Slowly rising to the surface, the Amphibian shaped a course towards the harbour of Nalcuanho. In less than an hour, Calderia would have its former President within her territory. What would be the nature of his reception?

CHAPTER XVIII

DON MIGUEL TAKES THE FIELD

"I feel quite sorry for that poor O'Rourke," exclaimed Dick. "He's sitting in his cabin looking the very picture of misery. I can quite sympathise with him."

"Yes, it's hard luck when you lose your nerve," agreed Holmsby, for now the excitement of the flight and subsequent attack was over the British officer looked at Don Miguel's failings in a different light to what he had hitherto done.

Holmsby had relinquished the wheel to the Calderian quartermaster on approaching the harbour of Nalcuanho. He had never before negotiated the intricate entrance, and, unwilling to take further risks, had left the navigation in the hands of those who were more capable of taking the crippled Amphibian betwixt the rocks and shoals that, for a distance of three miles, render the channel to the harbour of the capital of Calderia one of the most dangerous of all South American ports.

"Look here," continued Holmsby. "I'm horribly sorry for the poor fellow, too. Suppose we try and buck him up."

It was a very dejected Don Miguel who rose to meet the two Englishmen as they knocked and entered his cabin. He was certainly calmer, but was still labouring under the agitation of his mind.

"Gentlemen," he began, "I must most deeply apologise——"

"No need, Don Miguel," exclaimed Holmsby briskly. "We have come to tell you that we are about to enter Nalcuanho Harbour. In another half an hour Calderia will greet its deliverer."

"Yourself."

"No, señor: you are the person whom I refer——"

"But after my regrettable——"

"That, señor, is a closed book. You can and must play your part."

"My part," repeated the Calderian bitterly. "My chance is gone. I am disgraced, not only in your eyes, but in the sight of my crew. In another hour the news will be shouted from all the housetops of Nalcuanho. You, Mr. Holmsby, will be the hero of the Calderian people."

There was nothing hypocritical in Don Miguel's words. It was a straightforward declaration of incompetency. The man realised his position.

"Take another view of the situation," said Reginald. "Your chance is only just about to take place. It was your brains that evolved the Amphibian—that you must admit? Good. Now, to continue: an unfortunate attack of nerves incapacitated you. More by sheer luck than anything else I managed to see this business through. That was all. Both Mr. Tresillian and I saw your state and knew the reason; but of the crew, though they saw you lying on the floor of the conning-tower, none knew what had happened. Supposing we treat your case as an injury to the head received in action?"

"You mean it, señor?" asked Don Miguel, hope reviving in his breast.

"Certainly. But, remember, another time you must act the man. I'll say no more, Don Miguel. We are nearly in harbour now, so pull yourself together. For our part we'll do our utmost to see you through."

With the Calderian ensign flying proudly in the breeze, the shattered Amphibian passed between the crowded pier-heads and moored alongside the Inner Mole.

Calm and collected, yet deathly pale, Don Miguel O'Rourke, dressed in his gorgeous uniform, accompanied by his two English companions, appeared on deck.

In an instant Calderia recognised the commander of the vessel that had driven off the hostile fleet as its former President, and, with loud and repeated "Vivas," the crowd pressed and swayed on the quay-side, their shouts absolutely drowning the Calderian National Anthem that was being played by a military band with all the power at its command.

"You are all right now, señor," whispered Dick encouragingly. "The people are solid for you."

As O'Rourke stepped ashore, the Alcalde greeted him warmly in the name of the people, and, almost mobbed by his enthusiastic compatriots, the ex-President was carried shoulder high to a carriage.

"Where are my English friends?" he shouted, and the cry was taken up by the crowd. "El Englese, el Englese."

Reginald and Dick had modestly retired to the seclusion of the Amphibian's conning-tower; but in spite of their protestations they were made to come out of their retreat and escorted to the carriage in which Don Miguel and the Alcalde were already seated. Preceded by the band, and escorted by the excited populace, who insisted upon unharnessing the horses, the carriage was drawn in triumph to the City Hall.

During this semi-regal progress, Don Miguel had much food for reflection. He pictured the self-same street a few short years ago, when he was stealthily creeping along the deserted thoroughfare by night to escape the fury of the mob, perchance composed of the same men who were even now cheering him to the echo.

As for Tresillian, who knew not the Calderian temperament, he "rather enjoyed the fun," as he afterwards expressed it; but Holmsby, with his characteristic manner, was making good use of his eyes by noting the effect of the bombardment.

Altogether the Republic of Calderia was in a strange predicament. There had been a revolution within a revolution. The Extremists, who had been so active in the downfall of Don Miguel O'Rourke, found that their ideas did not at all coincide with those of the former co-revolutionaries—the Retardists. There was a split. The Extremists sought the aid of the neighbouring Republic of Talpico, while the Retardists, compromising with the Moderates—the party who wished for the recall of Don Miguel O'Rourke—found themselves beset by the Talpican navy and army and threatened by civil war to boot.

The subsequent bombardment of Nalcuanho, though interrupted by the timely arrival of the Amphibian, had caused considerable damage, not only to the fortifications, but to municipal and private buildings as well; but, curiously enough the popular outcry was not against the sister republic but against the Extremists whose action had been the means of causing the Talpican invasion.

But though the city of Nalcuanho was for the present relieved of the horrors of bombardment and investment, a real danger still existed within the boundaries of Calderia.

The Extremists, under the leadership of the President of their choice, General Guzman Lopez, held the southern portion of the Republic in conjunction with the Talpican army. Even if the allies did not carry out their boast of marching upon Nalcuanho, no peace could be assured until the work of driving the insurgents and their Talpican friends through the passes of Sierra was accomplished.

Don Miguel could not have arrived at the capital at a more opportune time. Amid the acclamations of the populace, he was once more made President without the necessity for an election—for the simple reason that there was no one in Nalcuanho to oppose him.

Steps were immediately taken for the suppression of the insurrection and the expulsion of the Talpican army. The Third Reserve was called out, the forces of the Republic reorganised, and in less than a week the Calderian troops were ready to take the field, led by the President in person.

But during that week Don Miguel had been busy in another direction. The Amphibian—the Republic's greatest asset—was being repaired, under his personal supervision so as once more to bear her part in the air; but, with considerable forethought, it was given out that her sphere of operations would be confined to the sea, with a view to making a salutary attack upon the Talpican fleet.

This had the effect of keeping the fairly powerful Talpican fleet within its harbours, for the Amphibian was regarded with feelings of terror by the seamen who had witnessed the appalling destruction of the Libertad. Talpico had still a strong squadron, whereas Calderia, with the exception of a few river gunboats, had no warships.

True to their word to see the President safely through, Reginald and Dick offered to accompany Don Miguel to the front.

"I have better work for you, señors," replied Don Miguel. "Within three days the Amphibian will, I trust, be again fit for service. Since you, Mr. Holmsby, know almost if not quite as much about the handling of her as I do myself, I wish that you will take command of her and bring her to the fighting-line. I am indeed grateful for your aid. Your advice to play the man I mean to follow. If, therefore, in action I am fated to fall, I trust it will be with my face to the foe. Should total defeat overtake my army, all will be lost as far as Calderia is concerned. My ambitions will be crushed, my life's work ended, for I vow never to leave the field alive and dishonoured. Should that unfortunate event take place, please understand that the Amphibian is yours to do with as you wish. Moreover, I have written to my agents in Paris—here is their address—telling them, in the event of my death, to hand over to both or either of you the documents relating to the secret of the composition of helia. Now I think I have made myself clear. To-morrow we set out for the frontier. Within a week we ought to be in touch with the enemy, and by that time I can hope for your co-operation with the Amphibian."

"Good luck to you, señor," exclaimed both the Englishmen. "For our part we'll do our best."

At daybreak on the following morning the van of the Calderian army entrained, a single line of rails communicating with Estores—a town fifty miles from Nalcuanho on the edge of the vast plain that stretches from the Rio del Este to the foot of the sierras. Throughout the day train after train left the capital, each packed with troops. The men, though somewhat lacking in discipline, were full of ardour and well armed with modern rifles. The majority were mulattoes; a few of the picked regiments only being composed of Creoles. Neverthelesss, they compared favourably with the land-forces of the Republic of Talpico, and, under the usual conditions, could be relied upon to give a good account of themselves.

Loyally Holmsby and Tresillian stuck to their task of superintending the repairs to the Amphibian. Day and night they took turns to keep the Calderian workmen at high pressure till the reconstruction of the envelope and aerial propeller neared completion.

Every day for five days messengers reached the town of Estores with news of the advance of the army, whence the information was telegraphed to the capital; but on the sixth day came an ominous break in tidings from the front. Excitement was at fever-heat, but throughout the tension of public alarm the Englishmen kept cool and collected, directing their attentions solely to the matter entrusted to their care; and at daybreak on the morning of the seventh day following Don Miguel's departure, the Amphibian rose majestically in the air and headed towards the distant sierras.

CHAPTER XIX

THE VINDICATION OF THE PRESIDENT

In less than seven hours the Amphibian covered the distance that had taken the Calderian army seven tedious days to accomplish, and shortly before noon the blue outlines of the rugged sierras appeared in sight.

Holmsby had already given the order to clear for action. The quick-firers were placed in position, and every man was at his post, equipped with a neutraliser in the event of a catastrophe to the airship, the speed having been reduced to twenty miles an hour so as to enable those on the promenade-deck to conduct their observations in comparative comfort.

It was a broiling day. The sun's rays poured vertically upon the huge bulk of the Amphibian, and in spite of the draught caused by her passage through the air, the metal deck plates and stanchions were almost too hot to touch with the hand, while the rubber-soled shoes of the officers and crew were rendered almost viscous by contact with the deck.

Suddenly above the sharp buzz of the aerial propeller, Tresillian detected the long-drawn sound of artillery and musketry fire.

"They've started, Rex," exclaimed Dick, pointing to the still distant range of mountains.

"Eh? What direction? Where's my glass?"

"Away more to the right, I fancy," replied Tresillian, handing his comrade his binoculars. "Can you see anything?"

"By Jove, I can," replied Holmsby. "One of the armies, at any rate."

"Then where's the other?"

"Entrenched or hiding in the long grass, I fancy. But what a one-sided place to choose for a battle: where the mountains meet the plain. One side is nothing but good cover and the other is as flat as a table."

Side by side the two Englishmen stood looking through their glasses at the still-indistinct line of grey-coated troops while the Amphibian's course had been altered so as to take her to the scene of battle.

Presently Holmsby brought his open hand down heavily upon the stanchion rail.

"Now I see what it is," he exclaimed. "We're a trifle too late to be of much use. That line we see is in reality both armies. They are having a fine set-to, but, by George, what a disregard for all modern tactics."

In a very short space the Amphibian was hovering over the battlefield at an elevation of nearly five hundred feet. It was as Holmsby had remarked, a hand-to-hand fight: the science of present-day warfare was totally lacking.

Don Miguel had opened the attack earlier in the day by a furious cannonade upon the Talpican defences. The invaders, possessing only light mountain artillery, were completely out-ranged, but in spite of their terrible ordeal stuck gamely to their trenches and the splendid cover afforded by the natural ruggedness of the ground at the base of the sierras.

At length, after four hours' incessant artillery fire, Don Miguel, unable to restrain the ardour of his troops, gave the order for a general attack, and no sooner did the bugles blare out the advance than the whole army, save the artillery, dashed forward with the utmost élan.

The sight of their advancing foes was enough for the Talpican soldiers. They, too, did not hesitate, but, firing an irregular volley at 800 metres, rushed pell-mell to engage their attackers.

The total length of the line of attack was barely two miles, the men being bunched together in close formation instead of the recognised open order, and in less than ten minutes from the beginning of the Calderian advance the opposing forces met.

It was more like a conflict between two savage tribes than a battle between two armies equipped with modern weapons. Beyond the first two or three straggling volleys few shots were fired on either side, but with bayonet, clubbed rifle, or the equally formidable machete, the foes met in deadly earnest.

Up and up swarmed the light grey clad soldiers of Calderia, only to be hurled back by the dark grey troops of Talpico, till the long line of struggling men appeared like a vast writhing serpent when viewed from the Amphibian, whose crew could see everything with the greatest ease, yet could not lift a finger to help in the conflict lest they should injure friend as well as foe.

Slowly yet surely the Talpicans gave back under the relentless fury of their attackers, but even as they did so the ground was dotted with grey figures, silent in death or writhing in agony.

Unseen in the heat of the battle the Amphibian hovered above the hardly-contested field, the Calderian crew hardly able to control their feelings at the undoubted success of their compatriots, while the Englishmen, calm and collected, were trying to distinguish the figure of Don Miguel O'Rourke. There was nothing to give them any sign of the President's presence, for neither side bore the colours of their respective republics, while officers and men were, in active service, dressed almost alike, the former being invariably dismounted.

Suddenly the left wing of the Calderian army began to give back. The Talpican right flank, reinforced by the rebel Extremists, instantly took advantage of the retrograde movement and pushed home a counter-attack with irresistible force till the light greys turned and fled in utmost disorder.

The cries of dismay and rage from the crew of the Amphibian increased when they saw the Calderian centre begin to waver. Should the panic spread, the day would be hopelessly lost. Some of the men went so far as to beseech Holmsby to drop one of the high explosive bombs upon the Talpican wing; but this he sternly refused to do, knowing that in the terrific explosion friend as well as foe would be involved in certain destruction.

"We'll drop to within 30 metres," he assured his crew. "No doubt the mere sight of the Amphibian will turn the fortunes of the day."

"Look!" exclaimed Dick. "There is Don Miguel."

"Where?"

"Stand here and look just above this stanchion. More to the left—do you see that knot of men wedging their way into the dark grey troops? See that man with his handkerchief bound round his head? That's O'Rourke: I saw it was he when he turned his face just now."

"So it is, by Jove!" said Holmsby. "He's fairly in the thick of it."

The sub-lieutenant spoke truly. Almost surrounded by the hostile troops, the butt of every bayonet and clubbed rifle within arm's length, the President of Calderia seemed to bear a charmed life. Already a bullet had grazed his forehead, but maddened rather than hurt by the wound he threw himself into the thickest of his foes. Nothing seemed able to withstand the sweep of his sword, while his example served to encourage his discomfited followers. Taking heart they rallied, and by a supreme effort thrust back their opponents till the Calderian centre pierced the Talpican line.

Meanwhile the enemy's right flank had strayed far from its original position in pursuit of the demoralised wing. Unless the fugitives could be brought to rally, the centre would be threatened with a flank attack.

"It's about time we stopped this useless slaughter, Dick," exclaimed Holmsby. "We'll give them a shot or two."

With the Calderian ensign floating proudly aft, the Amphibian swooped down to within two hundred feet of the ground, and at Holmsby's order the crew let fly two rounds with the fore quick-firer, the shells bursting harmlessly at a distance of three hundred yards to the rear of the Talpican centre.

Although the rifle firing was very desultory, cold steel doing most of the work, the din raised by the combatants almost drowned the sharp reports of the airship's gun. But the detonations were sufficient to attract attention. Both sides temporarily ceased their desperate attack and counter-attack and gazed skywards.

A yell that was meant for a cheer burst from the throats of the Calderian troops, while the Talpican forces, having a wholesome dread of the vessel that had paralysed their naval strength, gave back and soon broke into headlong flight.

Most of the Talpican officers made for their horses, mounted and galloped off for dear life, leaving their men to shift for themselves. Throwing away their arms as they ran, the fugitive soldiers made for the mountain pass, the mouth of which was barely two miles from the field of battle. Had Holmsby wished he could have dropped a high explosive charge into the gorge and sealed the demoralised invaders in a trap; but this he humanely refused to allow his crew to do. Even as it was, many of the fugitives were shot down by their victorious pursuers, who gave no quarter, ferociously slaughtering every wounded Talpican they came across.

"What bloodthirsty brutes!" ejaculated Tresillian, as he gazed at the scene of slaughter below them.

"They are," assented Reginald. "It's their nature. During their war of independence a hundred years ago their forefathers fought thus, giving and expecting no quarter, and a century of republicanism has apparently changed them but little."

"This will end the war, I think," said Dick. "Those unlucky beggars have had quite enough. The question is, Rex, what are we going to do now?"

"Do? Go home again, of course. I've carried out the instructions of my superiors to investigate—although I don't mind telling you I fancy I've somewhat exceeded my orders—so there's nothing left but to return and make out my report."

"You're following the example of Nelson at Copenhagen, Rex—interpreting your orders in a somewhat peculiar manner."

"Then I hope the sequel will be as successful, old man. Even Nelson would have found himself in a hole had he bungled over the business. But what's amiss now?"

Several of the crew grouped upon the forepart of the promenade-deck were gesticulating violently and pointing in the direction of the tallest peak of the sierras. Following the direction indicated, Reginald and Dick simultaneously gave vent to a surprised whistle.

Soaring over the mountains, and looking like a small dot in the brilliant sky, was an airship.

CHAPTER XX

TREACHERY IN THE AIR

"What's her little game, I wonder," exclaimed Holmsby. "An airship in these parts is a bit of a novelty. We must push forward and see what her intentions are."

"Hadn't we better signal to Don Miguel first?" asked Tresillian. "It would be well to warn him, since I don't suppose she is yet visible from the ground."

"It will mean descending again till we get within hailing distance," objected Holmsby. "Since the wireless telephone was knocked out of gear during our fall from the sky we have to rely upon the megaphone or the semaphore. During that time this mysterious craft will have sailed right above us, and that is like the advantage of the weather-gauge in the good old days of sailing line-of-battleships. So up we go."

Ordering another helia charge to be inserted in one of the reserve ballonettes, Holmsby took his place in the conning-tower. In a few minutes the Amphibian rose vertically to a height of 3000 metres and at a speed of ten knots forged ahead to meet her supposed rival.

"Stand by with the for'ard quick-firer," was Holmsby's next order in Spanish. "But don't fire till I give the word."

The oncoming craft was now clearly visible. She was at least four hundred feet in length, and of the non-rigid type. She differed greatly in appearance from the Amphibian, having a slung platform in place of the latter's promenade-deck, while the motive power was imparted to four propellers, two on either side of the long "nacelle." On this platform were three fairly large deck-houses, the foremost being triangular in shape so as to offer less resistance to the wind. As far as Holmsby could see, she carried no guns, but on each side of the for'ard deck-house was a searchlight, capable of throwing a beam well ahead with a good elevation, abeam, or vertically downwards.

When within half a mile the strange airship suddenly ported her helm, and, describing a half-circle, brought up broadside on to the Amphibian. As she did so the stars and stripes of the U.S.A. fluttered in the breeze.

Holmsby immediately put his helm hard-a-starboard, with the result that the two vessels were now slowly gliding in parallel lines at a distance of about eight hundred yards apart.

"Airship ahoy!" hailed Reginald, who had gained the promenade-deck. "What craft is that?"

"The Black Eagle of Boston, U.S.A.," was the reply, every word being clearly audible in the rarefied air in spite of the intervening distance. "Is Don Miguel O'Rourke on board?"

"No," replied Holmsby, surprised at the question.

"Then I reckon I'm tongue-wagging with Sub-Lootenant Reginald Holmsby?"

"You are," assented Reginald, still more surprised at the American's latest question. "How did you know my name?"

"Well, considering that you and Mr. Tresillian have had your names given in every paper as being kidnapped by an airship belonging to Don Miguel, it's not to be wondered at."

"We heard we were dead."

"P'raps," replied the American. "But we're here to see something of the scrap: all picture rights reserved for the Boston and Salem Electric Star Picture Company."

"Take care you don't get a shot through your gas-bag," cautioned Reginald. "It's a risky business getting within rifle range."

During the conversation the two craft had converged so that they were now less than two hundred yards apart. There were four men only visible upon the platform of the Black Eagle, the individual who had hailed, leaning against the bulkhead of the 'mid-ship cabin.

"Say, are you certain the President isn't aboard your hooker?" he continued.

"I said he was not," replied Holmsby, somewhat nettled at being doubted.

"That's a great pity."

"Why?" asked Holmsby.

"This!" shouted the man, dodging behind a screen.

Before Holmsby could act or even utter a warning shout a flash followed by a deafening report leapt from the 'midship cabin of the airship, and a two-pounder shell struck the Amphibian just abaft the conning-tower. Penetrating two of the ballonettes and one side of the inner shell that formed the body of the submarine it burst with a terrific detonation, shaking the Amphibian like a leaf from bow to stern.

Giving a sharp list to port the victim of the treacherous attack began to drop rapidly earthwards, while, simultaneously with the discharge of another gun, the projectile of which skimmed harmlessly over the Amphibian's deck-rail, the mysterious airship dropped several bags of ballast and shot upwards for nearly another thousand feet.

Even as she did so three men emerged from the deck-house and waved their hands at the stricken Amphibian.

In the midst of peril both Holmsby and Tresillian recognised the miscreants—they were the occupants of motor-car F.O. 445.

Fortunately the engineer, in response to Holmsby's orders, thrust another helia cylinder into another of the reserve ballonettes, which had been unaffected by the concussion, and at less than three hundred feet from the ground the Amphibian recovered herself, though still retaining a decided list.

"Let her down gently," ordered the sub., and with hardly a tremor as the helia hissed through the valves the Amphibian sank gently to earth on a broad ledge betwixt two towering peaks of the sierras. By this time the treacherous airship heading rapidly southwards, had vanished beyond the saw-like crests of the mountains.

Directly the vessel was made fast bow and stern, the Englishmen, accompanied by the engineer and the bos'un, entered the wrecked portion of the submarine. No doubt the rogues thought that the gas in the Amphibian's ballonettes was highly inflammable, and that the explosion of the shell would ignite the contents of the envelope; but, although they saw that the anticipated disaster did not take place, they were convinced that their diabolical plan had succeeded inasmuch as the Amphibian appeared to fall, completely wrecked, upon the jagged rocks of the sierras.

The damage was serious enough. The projectile had bored a small circular hole through the metal plating of the submarine, but had failed to penetrate the other side; the explosion had practically wrecked the whole of the interior abaft the central compartments.

The motors had been rendered unserviceable, the main shafting was fractured in places, while the stores, flung from their duralium cases, littered the floor, the provisions being badly spoiled by the thick brown dust from the explosion.

The Calderian engineer burst into tears and began wringing his hands at the sight of his crippled motors. They were done for, he declared—they would never be of use again. The Amphibian, perched half-way up the precipitous sides of the mountain, would be helpless.

"It might have been worse, Rex," said Tresillian. "Imagine the result if the shell had burst in the for'ard part where all our explosives are stored."

"It's a mystery to me how the concussion failed to explode them," replied Holmsby gravely. "We've still a lot to be thankful for."

"What's to be done now?"

"Done! why to get back to Nalcuanho as soon as we can," said Reginald resolutely.

"How? We can't use the motors."

"True; but where there's a will there's a way. We must wait for a favourable breeze, and then we'll sail back. The Amphibian is still capable of being supported in the air; it is merely a question of time."

"Time, yes: but in the meantime we may starve."

"Dick, you are a confounded pessimist. Have faith."

"Faith won't feed an empty stomach, my dear fellow."

"Think yourself fortunate that you still have the faculty of feeling the pangs of hunger. Now to work. I'll send in some of the crew and you can see that they clear this awful muddle away. Examine the stores; if they are spoiled, heave them overboard. We can't afford to carry useless lumber. If not, put them by. Meanwhile I'll see if the outer envelope and the two damaged ballonettes can be temporarily repaired."

"All right, Rex. I'll do my part. But when we reach the capital what do you propose to do?"

"Do? Why, what do you think I ought to do? I'll tell you. In less than a week after our return the Amphibian, with myself in command, will be off in pursuit of the treacherous airship. I fancy I've a few old scores to pay off against Messrs. F.O. 445 & Co."

"Rex, I thought you were not revengeful," said Tresillian in mock reproach.

"Neither am I. But you can't always twist a dog's tail and not expect him to bite. Now, I'm off. Keep those fellows at it, for every moment is precious."

So saying Holmsby re-entered the central compartment and, ascending the iron ladder, gained the promenade-deck. It was a strange sight that met his gaze. The Amphibian was lying upon a broad ledge of grass-grown earth that was shut in on three sides by the almost sheer cliffs towering to a height of three thousand feet. On the remaining side was a corresponding drop of over a thousand feet. Far below, Holmsby could see a fertile valley through which a mountain torrent leapt like a silvery thread till lost to sight behind a rugged spur. Beyond the valley the mountains towered almost as high as the one on the side of which the Amphibian had found a place of refuge.

"This place is well sheltered from all but northerly winds," thought the young officer. "And a north wind is not what we want. The bother is that with a favourable breeze there will be no wind at all on this side of the cliff, or, what is worse, a baffling eddy. Ah, that reminds me. If the so-called Black Eagle should return and drop half a hundredweight of explosives on the Amphibian while she's lying here it would be a case with us, I fancy. I think I'll send a man up the cliff to keep a look out.—No, I won't, by Jove. I'll go myself."

"Dick!" he shouted down the hatchway. "I'm going aloft."

"Aloft, where?" replied Tresillian, who was busily engaged with some of the crew in shovelling a sticky mixture of calcined bread and oil and dust into buckets.

"Up the cliff. I'm going to have a look round."

"Shall I come with you?"

"Better not."

"Is it safe?"

"Safe as anything. I'll be back in less than a couple of hours."

Taking with him his revolver and twenty-four rounds of ammunition, a pocket compass and his binoculars, Holmsby gained the ground by means of a rope ladder, while one of the crew followed with two neutralisers.

Both of these the sub-lieutenant fastened to his back. One was charged; the other, for use in case of emergency, was not; while, as an additional precaution, Holmsby thrust four spare cylinders into his coat pocket. In his hand he carried a short staff shod with a steel point and bent prong somewhat resembling a boat-hook.

Giving one upward glance to see that no projecting crags impeded his way, Holmsby leapt. Fully fifty feet he shot up, then, as he was on the point of returning earthwards, a gentle thrust with the pole gave him a fresh impetus. It was exhilarating yet almost tireless, Holmsby thought as, leaping from crag to crag, taking advantage of every crevice and assisting his ascent by clutching at the tufts of coarse grass that festooned the face of the cliff, he rapidly left the Amphibian far beneath him.

In exactly fifty-five minutes from the commencement of his climb, Holmsby reached the summit of the cliff, and, holding on to the scanty herbage, lay at full length in order to remove and secure the still buoyant neutraliser.

There was no sign of the treacherous airship. As far as he could see there was nothing but a saw-like ridge of gaunt peaks, some considerably higher than the rest being snow-capped.

"There's not a thing that I can lash this contrivance to," remarked Reginald to himself, as he looked about him. "I don't want the thing to break away and soar skywards, even though I've a spare neutraliser. Well, I suppose I must drive this spiked staff into a cleft in the rock and make the thing fast to it."

Acting on his impulse, Holmsby rose to his feet and began to walk cautiously along the mountain-top, but, though rugged, there was no fissure deep enough to receive the pole and keep it securely.

Suddenly a gust of wind swept over the summit of the cliff. Holmsby heard it whistling ere the blast reached him, and, realising his danger, threw himself forward. But owing to the retarding influence of the neutraliser the movement was necessarily slow. Before he could secure a grip the gust caught him, and, lifted like a feather, he was in a moment whirled far out over the cliff. Beneath him was a sheer drop of nearly four thousand feet.

CHAPTER XXI

THE PRESIDENT'S CHOICE

Desperately gripping his boat-hook like the proverbial drowning man grasps at a straw, Holmsby found himself being twisted and turned in all directions by the powerful wind-eddies. At first he feared that he would be swept far across the valley to the corresponding range of mountains; but by degrees he felt himself dropping lower and lower till the cliff from which he had been hurled began to break the force of the wind. His descent was more direct and rapid now that he had struck a belt of comparatively still air. Yet this rate of his downward fall was not great enough to cause him any discomfort beyond the anxiety as to what would happen when he reached the ground.

The descent was even more exhilarating than the ascent, and Reginald found himself wondering whether the general use of the neutraliser would in days to come evolve a new pastime. Ski-ing and tobogganing were not to be compared with it, he decided.

As he neared the ground the air in the lower part of the vast gorge was considerably denser than at the greater altitude, and in consequence his fall was retarded to such an extent that the impact with the ground occasioned him little more discomfort than a leap of six feet under ordinary conditions.

Holmsby had fallen at least two hundred yards from the base of the cliff, the intervening distance being thick with thorn-bushes. Realising that it would be a matter of considerable difficulty to crawl through this almost impassable barrier, hampered as he was, Reginald decided to release the remainder of the helia charge from the neutraliser.

Over and over again he had to retrace his steps and attempt another route, while at times the bushes were so tall and thickly leaved that the towering cliff and the blue sky over his head were both invisible, but, guided by his compass, Holmsby stuck gamely to his task.

It took him quite half an hour to traverse two hundred yards, and it was with feelings of relief that he found himself on an open space, close to the base of the cliff. Evidently this was a path through the mountain-pass, for there were signs of horse-traffic, although not sufficient to check the growth of weeds and thistles. A little to his right was a scar or projecting ledge of rock beyond which the rough path was lost to sight.

"Although these neutralisers are marvellous devices they are a regular nuisance," he remarked, as he began to recharge the one that had served him so well. "Why can't they be charged from the front? I am afraid I shall have to use it in the same manner as Dick when he escaped from our old acquaintances in F.O. 445."

Just then the withered stump of a tree caught his glance.

"Good idea. I'll lash the neutraliser to this tree, charge it, and slip the belts over my shoulder. Then I can cut away the lashings and make a fresh start."

Acting on this inspiration, Holmsby walked over to the stump and tested its condition. It was sound enough for his purpose. But when he searched for some cord, which he had felt certain he had placed in one of his pockets before starting, the desired article was not to be found.

"I must sacrifice my handkerchief, I suppose; and here are some withies—as strong as an inch rope," he thought.

Just as Holmsby had securely fastened the neutraliser in position and was about to insert the helia cylinder, the distant clatter of horses' hoofs caught his ear. There was no time to unlash the metal case, so, hastily covering it with a handful of rushes, the sub. made a dash for cover behind the intervening crag.

Nearer and nearer came the sound, now sharp as the iron-shod hoofs struck the bare rock, now deadened as they sank upon the soft earth; but just as Holmsby expected the horsemen to appear in view, he heard a voice exclaim in Spanish, "Halt!"

"This is a regular nuisance," said Reginald to himself. "I don't want to be penned up here for the next hour or so while those fellows are having a meal. I may as well have a look at them and see who they are."

Holmsby looked at the crag above him. Close to where he stood was a fissure extending in a diagonal direction almost to the top of the rock, a distance of twenty feet from the ground. Stealthily he ascended, making good use of his steel-shod pole, till, unnoticed and unheard, he gained the summit of the projecting ledge. Here, without much fear of discovery, he could command an almost uninterrupted view of what was going on beneath him.

There were nearly a dozen Talpican irregular cavalry; some were engaged in collecting wood for a fire, others were hobbling their horses and unloading their packs; but two of them, evidently officers, were talking in a threatening manner to a prisoner.

The prisoner was Don Miguel O'Rourke.

The President of Calderia was in a most undignified position. He was on horseback, his legs fastened under the animal, his arms secured behind his back, while a guerilla with his rifle grounded stood ten feet behind him.

Don Miguel showed no signs of fear; there was a look of haughty indifference on his face, although he answered his captors readily enough.

"You see, señor," said one of the officers. "You are entirely in our power. Consider your position. Your wonderful airship is hopelessly destroyed, your English friends are dead, but that is a pity since I should like to see them taken prisoners and shot as filibusters. We make no secret of the fact that Don Robiera Sanchez, who, after attempting to prevent the Amphibian from leaving England, came here in the airship Sol d'Este, was responsible for that achievement. His mechanical skill and ingenuity almost rival your own. But to proceed. Our fleet, now free from attack, will proceed to Nalcuanho and complete the work that it had begun. Talpico will have ceded to her the territory she demands, and in return Don Robiera Sanchez will occupy the presidential chair of Calderia. Now, this is our alternative. Give us the secret of the mysterious agency that enabled you to raise the Amphibian from the depths of the sea——"

"Never, señor——"

"Not so fast, Señor O'Rourke. Either the secret or the garotte. Picture yourself in the centre of the Plaza, the public indignity, the first squeeze of the instrument—and, señor, having your throat compressed by an ever-tightening metal collar is not at all pleasant—then a hasty burial in an unmarked grave."

"Three times you have placed your base proposal before me, señor," replied Don Miguel calmly. "In every case my reply has been, and will be, the same. I, perchance, have failed, but there are others to carry on my work. Rest assured that the desired secret will never be known to any Talpican nor will Talpico occupy a foot of Calderian territory unhindered while a single Calderian remains in arms. So, I beg of you, save your breath for other purposes."

"Caramba! To-morrow you'll tell another tale, Señor O'Rourke. We rest here this night; at sunrise we start again, and ere noon will be at El Cayo. See, the sun is sinking behind the sierras. Take heed lest you see it set for the last time."

During this conversation Holmsby's brain was actively thinking. Don Miguel must be rescued—but how? One way would be to recover the neutraliser, scale the cliff, and bring the crew of the Amphibian to the aid of their President; but the risk of Holmsby being discovered, and also the fact that night was approaching, negatived the proposal. There was another way.

Placing his spare cartridges beside him on the rock, and making a cursory examination of his revolver, Holmsby braced himself for the coming ordeal. He had no qualms at suddenly opening fire on the unsuspecting guerillas, since they had threatened their helpless captive with death. Also, he was perfectly aware that had either he or Tresillian fallen into their hands they would have been summarily shot.

Resting the barrel of his weapon upon the edge of the rock, Holmsby depressed the muzzle till the sights were in line with the intersection of the guerilla captain's cross-belts. A gaudy clasp on one of the leather straps made a splendid mark, yet the Englishman hesitated to press the trigger.

The Talpican was indisposed to leave his captive in peace.

"You dog—obstinate mule!" he exclaimed. "I am of a mind to have you whipped to help you change your mind. Curse you! Why do you treat me as dirt? Why won't you answer?"

Urging his horse nearer to the captive the guerilla captain raised his clenched fist. Holmsby could not see Don Miguel's face, but by his attitude it seemed that the President never quailed.

Before the threatened blow fell, the Englishman pressed the trigger, the heavy weapon kicked, and ere the bluish haze had cleared away, the coward lay writhing on the ground. Five times more the revolver spat viciously, and all but one shot took effect.

Jerking open the chambers and allowing the ejector to throw out the still smoking cylinders, Holmsby began to reload; but before he had completed this operation the survivors of the party were in flight. Some leapt into their saddles, others crouching ran by the side of their horses abandoning their fallen comrades, baggage, and prisoner in their panic to escape from what they imagined to be a numerous party in ambush.

But to Holmsby's consternation the steed upon which Don Miguel was bound began to follow the fugitives—hesitatingly at first, then increasing its speed. It was a risk, but the Englishman took it. Raising his revolver he aimed rapidly and deliberately at the retreating animal and fired. The horse staggered a few yards, sank on its forelegs, and rolled over on the ground with Don Miguel still bound in the saddle.

Sliding from his elevated position with more haste than caution, Holmsby gained the ground and ran to aid the Calderiari President.

With another shot he put the struggling animal out of his misery, then with a swift slash of his knife severed the thongs that bound O'Rourke's ankles.

"Señor Holmsby!" gasped the rescued man in astonishment.

"Hurt, señor?" asked Reginald, who saw that Don Miguel's face was deathly white.

"My leg is broken, I am afraid," replied the President. "The horse falling on it—but I heard you were killed?"

"Never in better health. The fresh air of the sierras suits me," assented Holmsby. "But we must be off in case these rogues pluck up courage and return. In another quarter of an hour you will be safely on board the Amphibian, I hope."

"The Amphibian? Do I hear aright?"

"Certainly, in spite of what you have just heard from that rascal," replied Holmsby, pointing to the motionless form of the guerilla captain. "She's damaged—badly, I fear—but I have hopes of getting her back to Nalcuanho. Now, Don Miguel, let me assist you."

The President, however, could not put his foot to the ground, His fears were realised: his ankle was broken. Holmsby looked upwards at the dizzy heights, then at the sky. The sun had disappeared behind the sierras, and darkness might set in at any moment.

"There's no harm in trying it," he muttered, and, darting off, he made his way to the spot where he had concealed his neutralisers.

Strapping one to Don Miguel's back, he charged it, then, replacing the one he had previously worn, Holmsby requested his companion to insert the helia cylinder. This done he picked up two rifles that the guerrillas had left in their flight and withdrew their ramrods. These he bound tightly to O'Rourke's injured limb, at the same time passing a leather belt under the patient's foot, so as to take the strain in mid-air.

"Now, señor," exclaimed Reginald. "Hold on tightly to me, and grin and bear it. Either we gain the Amphibian in another ten minutes or we will have to spend a most uncomfortable night with those dead Talpicans for company."

"I am ready," replied the President. "But can you manage to climb up with me on your back?"

"I'll have a good shot at it," said Holmsby resolutely. "Look here—I suppose we can't place two cylinders in one neutraliser? I have some spares."

"It's not worth the risk," replied Don Miguel. "There are two dangers: too much buoyancy and also the great possibility of the appliance bursting."

"Then that settles it," rejoined Reginald. "I don't fancy a thousand-foot drop. So, stand by—now."

And, kicking off with a vigorous thrust, Holmsby with his companion gripping him round the shoulders, began the hazardous ascent.

CHAPTER XXII

THE PERILS OF THE ABYSS

Up and up the almost sheer cliff Holmsby made his way, taking advantage of every convenient crevice or projection. Often he was compelled to stop, clutch at the rock with one hand while he wiped from his eyes the particles of dust that fell from above.

For the first five hundred feet the ascent was comparatively easy, although more than once Reginald had to ask his companion not to clasp him so tightly. Beyond that neither man spoke, nor durst they look down at the yawning gulf beneath them.

Holmsby was practically supporting a dead weight of a pound—the difference between the combined weight of the two men and the upward force of the neutralisers. It seemed but slight, but to lift even a pound up a vertical height of one thousand feet was in itself a severe strain.

Gradually it began to dawn upon the sub-lieutenant that something was amiss, but trying to console himself that it was the telling effect of the continuous strain, he stuck to his stupendous task with determination. But ere he gained another hundred feet the truth became apparent: one of the neutralisers was leaking.

Resolving not to say a word to alarm his companion, Reginald held on to a rock and rested a few moments ere he resumed his strenuous efforts, but his anxiety not to inform Don Miguel of the impending danger was relieved when the latter exclaimed:

"Dios, Señor Holmsby! My neutraliser is almost exhausted."

"I feared that it had been getting weaker for some time past. But courage; it is only a short distance to the summit."

Reginald spoke boldly, but he knew full well that it was a full three hundred feet to the broad ledge on which the Amphibian rested.

"Perchance the charge has been in use for some time," suggested O'Rourke.

"Impossible. I put a fresh cylinder into the neutraliser you are wearing. But I have some more in reserve. Can we recharge the thing now?"

"We must be careful to allow the helia to totally escape," said Don Miguel. "But what is to happen to us in the meantime? One neutraliser will not suffice for both."

"I see a fairly wide cleft just above us," exclaimed Holmsby. "So hold on while I make another effort."

It was now as if Holmsby were climbing alone without the aid of the neutraliser, and burdened in addition with a load on his back. Scrambling, clutching, heaving, and raising himself by sheer physical strength, he climbed foot by foot, his breath coming in laboured gasps.

"Good-bye, old comrade," exclaimed Don Miguel suddenly. "It's too much for us both. I'm going to let go."

"You'll do nothing of the sort," gasped Reginald "Hang on like grim death. I'm still going strong."

"No, Señor Holmsby, I know you cannot do it, burdened by my weight; so good-bye once more."

"Stop that," almost shouted the Englishman in desperation. "Stop that and hold on, or—or, I'll punch your head!" Ludicrous as the threat was under the circumstances, O'Rourke gave in to his companion's superior will, and Holmsby at length succeeded in gaining the scanty shelter afforded by the fissure in the face of the cliff. With a groan of utter bodily exhaustion he placed his living burden on the slightly-shelving rock and threw himself down beside his almost helpless companion.

It was indeed a place of refuge and that was all. The cleft was about four feet in height and three in breadth and extended inwards till the sloping floor met the also converging roof at a distance of not more than ten feet from the edge. Besides sloping outwards, the floor was fairly smooth, affording no foothold save the slight projection which Holmsby had made good use of when gaining the place of shelter. A slip would result in a headlong plunge upon the rocks several hundred feet below.

Cautiously loosening the valve of Don Miguel's neutraliser, Reginald allowed the remaining helia to escape and then withdrew the porcelain cylinder. It was perfectly dry. The fault lay not in the exhaustion of the chemical but in the fact that the water in the apparatus had either leaked or evaporated.

"All the spare charges we have will not help us now," exclaimed O'Rourke.

"Then it cannot be helped," replied Holmsby. "Supposing I give those fellows above a hail. They will either lower a rope or else another neutraliser."

Both men shouted again and again, but no welcome response came in answer to their appeal for aid. Strange as it may seem, the Amphibian, tucked away on the ledge, was completely inaccessible by waves of sound travelling upwards along the face of the cliff.

"Look here!" exclaimed Holmsby, after a few minutes' anxious wait. "I'll scale the remaining part of the cliff and bring assistance. My neutraliser is still active."

"For Heaven's sake don't leave me here helpless and alone," implored Don Miguel, his courage failing him after a struggle to keep up his spirits.

"Nonsense, man," exclaimed Reginald, almost roughly. "It's the only thing to be done unless we have to stay in this hole for the night."

"I cannot," almost screamed the now nerveless man. "The horrible gulf seems to want to drag me into its depths. Don't leave me, señor, I implore you."

"Very well, then," replied Reginald savagely, for, iron-nerved himself, the sight of a man in a pure funk always exasperated him. "We must make the best of it; but I warrant you'll be sorry for it before morning."

Since there was no place to secure his neutraliser, Holmsby released the remaining helia and unstrapped the apparatus. Then, better able to gain a footing on the shelving ledge, he gently dragged his helpless comrade as far from the brink as possible. He knew what to expect when a man with a broken limb has to pass many long and weary hours without medical attention; so to safeguard himself as well as his companion, Holmsby deftly passed the strap of O'Rourke's neutraliser round the ankles of the late wearer, placing the second belt in readiness should it be required.

Barely had he completed these preparations when the brief twilight deepened into night and intense darkness brooded over the valley. Though the horror of the gloomy depth beneath was hidden from sight, the thought of the awful gulf but a foot from where they were lying remained. Sleep was, of course, impossible, since the slightest involuntary movement might result in the two unfortunate men rolling over the brink of the tremendous cliff.

"Are you hungry?" asked Holmsby, after a while, anxious to break the dismal silence.

"Not very," replied Don Miguel. "Though it was early this morning since I had anything to eat. You see we started the attack upon the Talpican position at six. But I am thirsty—my throat seems as if it's full of burning sand."

This was a bad sign, Holmsby thought. He would have given much to have one of Don Miguel's injectors at the present moment. Had he one he would not have hesitated to render its inventor insensible and risked the remainder of the ascent in the darkness in order to obtain aid. He was also curious to learn the circumstances under which the President had fallen into the hands of the Talpicans, but, forbearing under present circumstances to question O'Rourke on this point, he wisely determined to let that information stand over.

Slowly the hours of darkness passed, till shortly after midnight, a vivid flash of lightning blazed across the sky, throwing the valley and the outlines of the distant mountains into strong relief, then leaving the two men blinking in the corresponding intense darkness.

The heavy peal of thunder that followed seemed to shake the solid rock. Holmsby gave an involuntary gasp and dug his heels more firmly into the precarious foothold. The vibration, intensified by the helplessness of their position, made it appear as if the ledge was on the point of bodily giving way.

Then the storm burst. Flash succeeded flash with great rapidity, the thunder rolled, and the rain descended in sheets. Fortunately there was no wind, although Holmsby momentarily expected the sudden vicious squall that almost invariably occurs during some period of the thunderstorm. He wondered what would happen to the Amphibian, only insecurely anchored in a dangerous position, where one blast from the northward would hurl her bodily against the rugged cliff.

Presently a steady stream trickled from the roof of the fissure and gradually increased in volume. This was to a certain extent beneficial, since Don Miguel could slake his thirst. Even Holmsby was beginning to feel the pangs of hunger and the want of something to drink, but when availing himself of the now copious gush of water, he could not help wondering what would happen if the stream became a torrent and swept the refugees from their confined haven of rest.

At length the storm passed, and although the water continued to run steadily it did not increase in volume. Nevertheless the rocky ledge was rendered so slippery by the moisture that the precarious holding-ground was made even more unsafe. Then, as Holmsby had expected, his companion began to grow restless. Symptoms of fever were beginning to appear, and ere long Don Miguel would be delirious.

Holding the hand of the tormented man, Reginald strove to calm his fears, both real and imaginary, and as he waited thus the peaks of the distant mountains began to grow visible through the darkness.

"Surely it is not daybreak," thought Holmsby, but as the light increased he saw that it was caused by the rising moon. In less than a quarter of an hour the valley was bathed in mellow light. This was comforting, and even the injured man seemed to find ease of body and mind with the welcome change.

But the rally was only temporary.

"Mr. Holmsby," he whispered, "the pain is returning. I fear it is more than I can bear. Place your hand in this pocket and you'll find a case. Inside is an instrument that you know how to use, so make good use of it."

The tortured man pointed to a small pocket behind the knee of his riding breeches, so cunningly placed as to be easily overlooked except by a most careful search. In it was a thin case about two inches square, and to Holmsby's satisfaction an injector was within.

"I carry it as a last resource," explained the President. "That needle is charged with a most virulent poison."

Holmsby's face fell.

"Here, this won't do," he exclaimed. "I'm not going to kill you, if that's what you want me to do."

"I do not. Be careful. In the lining of the case is another needle which will inject the anæsthetic only. It will keep me quiet for a few hours at any rate."

"You are quite sure about the needles?"

"Perfectly; now please hasten, for the agony is becoming intense."

Carefully extricating the needle and pneumatic pad from the case, Reginald stuck the point into the nape of Don Miguel's neck. The effect was instantaneous: the Calderian President was dead to all pain.

"A few hours, he said," thought the operator. "By Jove, I'll risk it."

It was a comparatively easy matter to charge and buckle on the neutraliser. Kept by its own upward pressure against the sloping roof of the hole in the rock it presented no difficulty to Holmsby, who, setting his back against it, drew the straps across his chest. In a few moments he was making his way up the face of the cliff, keeping as straight a direction as possible, in order to find the crevice again.

Good luck favoured him, for he gained the ledge upon which the Amphibian rested without much trouble. In the moonlight the huge bulk seemed to tower higher than usual, while from the conning-tower the beams of the two search-lights shot diagonally upwards. On the promenade-deck, silhouetted against the illumined face of the cliff, were the crew, all intently gazing upwards. Holmsby understood: the faithful fellows were watching and waiting for his return, only he came from a direction whence they least expected him.

"Hi, there, you Tresillian. What d'ye mean by switching on those search-lights?" he bawled. "Do you want the airship to find you out and blow you to smithereens?"

And with a magnificent leap Reginald gained the deck of the Amphibian and grasped his comrade by the hand.

Dick could not bring himself to utter a sound. He merely used Holmsby's arm as a pump-handle, while it was with the greatest difficulty that he could prevent himself from blubbering like a whipped schoolboy.

"It's all right, Dick. I'm not a ghost. If I am, I'm a pretty solid one, I assure you," his comrade expostulated; then turning to the crew, he told them in a few words of the precarious position of the President of Calderia.

For the next few minutes all was confusion and bustle. Men ran hither and thither, some donning their neutralisers, others bringing coils of ropes from the ship's store. While these preparations were in progress, Holmsby went below and helped himself to some food and a stiff dose of Calderian wine.

"Going down again, Rex?" asked Tresillian. "Can't I go and you stay here and superintend operations?"

"Impossible, old chap; you wouldn't find the place. I'm as fit as anything now. You stand by with six of the men. I'll take a length of fine cord with me. When I give three tugs, haul away on the life-line."

The rescue of Don Miguel was soon accomplished. Secured by a rope and buoyed up by a neutraliser, his apparently lifeless body was hauled up the remaining portion of the cliff, Holmsby and the men who accompanied him ascending with hardly an effort by merely holding on the same rope that was attached to the President's body.

On regaining the Amphibian the wounded man's limb was set in splints, and the bullet graze on his head carefully dressed, but Holmsby and Tresillian agreed that the sooner O'Rourke received proper medical attention the better it would be.

The return to Nalcuanho must be made at all costs, but how? Provisions were running short, the supply of water, though augmented by the torrential rain, was steadily diminishing, and unless a favourable breeze sprang up the crew of the Amphibian would be compelled to abandon their craft and make their way back to the plains on foot.

Three days passed, but still the north wind held with aggravating persistence. On the morning of the fourth day one of the crew raised the alarm that an airship was in sight.

Rushing on deck, Reginald brought his glasses to bear upon a small speck in the sky. The Calderian was right. Making her way rapidly in a southerly direction was the airship commanded by the treacherous Don Robiera Sanchez, the erstwhile owner of the fictitious F.O. 445. Either the airship was on the look out for the supposed wreck of the Amphibian or else it was on its way to assist in the second attack upon the capital of Calderia. The Amphibian helpless to repel an onslaught, was in a perilous situation. Should the Talpican airship discover her she was doomed to destruction; on the other hand, ere the crippled vessel could return to Nalcuanho, she would have to run the gauntlet since her rival had placed himself between the sierras and the capital.

"What's to be done now?" asked Tresillian.

"Done? Give me a favourable breeze, Dick," replied Holmsby, "and, by Jove, I'll make a fight for it."

CHAPTER XXIII

THE AIRSHIP THAT PASSED IN THE NIGHT

Early on the following morning Holmsby went on deck and, after receiving the reassuring report from the look-out that nothing untoward had occurred during the night, anxiously scanned the sky. There was not a breath of wind under the lee of the cliff, but at a great altitude light fleecy clouds were moving slowly in a northerly direction. What wind there was above was certainly favourable, but the vital question arose: whether the Talpican airship would intercept the Amphibian?

The latter was now little better than a balloon. The damaged compartments had been temporarily repaired, although patching the metal shell of the submarine was under the circumstances impossible. Motive power there was none, the airship being at the mercy of the winds. No doubt she could more than hold her own if attacked by her rival in mid-air, since by her superior raising power she could easily outsoar any hydrogen-filled craft, while her armament was still intact. But Holmsby did not wish to run unnecessary risks. For the time being, and until the Amphibian was thoroughly repaired, he would rather that Don Robiera Sanchez and his treacherous gang laboured under the delusion that the dreaded Amphibian was no more. There was also another reason. Should the Talpican airship discover the Amphibian scudding helplessly before the wind, she could easily keep to windward of her and wait till either the Calderian craft was blown out to sea or until she attempted a descent in the vicinity of Nalcuanho. In that case the Amphibian could be easily destroyed before the Talpican airship came within range of the high-angle firing guns of the forts. To men who were being attacked by the gnawing pains of hunger the prospect of being unable to take advantage of a wind that would soon blow them to the fertile plains of Calderia was exasperating in the extreme; but on Holmsby explaining the dangers and difficulties of a flight by day the Calderian crew readily gave way to the judgment of their English adviser.

Meanwhile Don Miguel was progressing favourably in spite of the lack of medical attention. The pure mountain air worked marvels, and, unless complications followed, his cure bid fair to be rapid and lasting.

Yet the mercurial temperament of the man fell very low, and Holmsby could see that he was in a fit of depression.

"I'm not fated to be a leader of men, Mr. Holmsby," he said plaintively. "At times I feel I have the energy and the power of mind; but when it comes to the point, alas, I know I am a miserable failure."

"Don't talk like that, señor," said Reginald. "It is only owing to the result of your condition. No man could have led his troops more gallantly than you did the other day."

"You saw me then?" asked O'Rourke brightening up.

"Saw you—of course we did. You fought magnificently——"

"And allowed myself to be taken prisoner a few minutes after the battle had been won. Again, my courage failed me utterly during the ascent of the cliff. I am no hero. As an inventor, with a knowledge of science, I hope I am above the ordinary, but as President of Calderia I feel that the realisations of my lifelong ambitions have fallen short of my expectations. Without the aid of you and your friend where should I be now?"

"You never know your luck," replied Holmsby sententiously; then, anxious in his modesty to divert the channel of Don Miguel's expressions of gratitude, he asked:

"How did you find yourself in such an awkward position after the victory?"

"I can hardly remember. The wound in my head was troubling me, although during the attack I scarce noticed it. Our men were in pursuit of the enemy. Somehow I found myself well in the rear, attended only by an orderly. I was on the point of going to rejoin General Saldanha and the rest of my staff, who were trying in vain to keep our men well in hand, when a volley from a thicket bowled the orderly over. Ere I realised it I was surrounded, made prisoner, and thrown upon a horse. My captors were all mounted and, riding with the greatest audacity round our straggling right flank, soon placed a safe distance between them and the battlefield."

"Couldn't you shout when they made you ride past the flank?"

"Shout, señor? My word! With a revolver pointed at one's head one does not care to waste breath in more ways than one. Those guerrillas are most daring men, and it was with the intention of either killing me or taking me prisoner that they lay in ambush while the rest of the Talpican army fled. Was it not your Shakespeare who made one of his characters say, 'I would give all my fame for a pot of ale and safety'? I would willingly give all I possess—even the secret of my great invention—to live my student days over again. But what do you propose to do now, Mr. Holmsby?"

Reginald told him of his plan of action.

"Excellent. You are what I ought to be, my friend. I have the initiative but lack the strength of will to carry out my intentions: you have both."

"Well, señor, I must be off, for there still remains much to be done. By the bye—have you a drawing of the motors on board? If so, we ought to be able to make a speedy job of assembling the new parts."

"My drawings are here," replied O'Rourke, tapping his forehead. "It is the only safe place as far as I am concerned. But since I am at present incapable of attending to my work I must needs leave it to others. Within three hours I will make rough drawings sufficient to enable the parts to be turned out or cast; but please remember that until I give you leave to do otherwise the secret of the motive power of the Amphibian rests solely between you and me."

It was half an hour before sunset that the crippled Amphibian rose slowly in the still air. Fearing that ere she cleared the top of the cliff she might sustain damage by colliding with the precipice, Holmsby had caused large sacks filled with grass to be slung around her bulging sides, while men armed with long poles were stationed on the deck to fend her off.

All went well till the airship was within fifty feet of the summit. Here the wind blowing strongly over the peaks of the sierras eddied treacherously. At one moment a fierce gale would strike the craft on the bow, at another the afterpart would be caught by a vicious blast. Swaying, pitching, and rolling, the huge bulk was helpless in the wind; but just as it seemed to be on the point of crashing into the rocky face of the mountains the true wind caught the Amphibian on the beam. The next moment the peril was past and the airship was being whirled rapidly northwards.

Holmsby gave a sigh of relief as he realised that all cause of anxiety was at present at an end, and rejoining Tresillian on the promenade-deck he had for the first time for some days a minute to call his own.

"Isn't that magnificent?" exclaimed Dick, pointing to the jagged peaks of the sierras, that alone of all the landscape were bathed in golden sunshine.

"Fine," replied Holmsby shortly. He had no inclination to study picturesque effects: his sole thoughts were on the question of whether the Amphibian would reach Nalcuanho before the moon rose.

"We don't seem to be moving very fast," continued Tresillian. "It seems more like being on a merry-go-round at a country fair, only no blaring organ to liven things up."

The Amphibian was slowly see-sawing, her bow describing a double loop while at intervals she would make a complete revolution on a horizontal axis; but, looking over the side, Holmsby noticed that the country beneath was apparently slipping past at a great speed.

"We're doing all right," he exclaimed cheerfully. "Forty miles an hour at the least. The nearer we get to the sea the steadier the breeze will be."

"But forty miles an hour is too great a rate for us to descend?"

"True; but with luck we ought to be on the coast at sunrise. In this country, like many other tropical parts, every evening the wind blows towards the sea, since the land gives off its heat quicker than does the water. Soon after sunrise the conditions are reversed, but ere the change takes place there is a lull for some hours. This calm I mean to take advantage of, if possible. Now, I'm going to turn in. Keep the watch on deck up to the scratch, and don't forget the barometer. So long as we are ten thousand feet in the air we won't come to much harm. But should anything unusual occur call me at once."

Bidding his comrade good-night, Reginald went below and turned in "all standing," so as to be ready for an emergency.

Left to himself, Dick paced the afterpart of the promenade-deck. His knowledge of Spanish was limited to a few words picked up during his stay on the Amphibian, sufficient to give a few orders, but not enough to engage in conversation. For'ard the watch on deck were talking volubly, but keenly alive to their duties, they maintained a sharp look out.

Darkness had now set in, and, though the airship's erratic behaviour was still noticeable, it was not so uncomfortable as it had been during the day when the sight of the earth beneath increased the sense of motion.

Hour after hour passed. Not a light was visible from the land, nor was the cheery glimmer of a lamp permissible on board. The crew, too, were deprived of the solace of their otherwise ubiquitous cigarettes. At what rate or in what direction the Amphibian was being blown it was impossible to tell. To Tresillian it seemed as if the vessel was floating idly in a void of impenetrable darkness; the stars, even, were invisible, for the stratum in which the airship was drifting was dense with a moist, freezingly cold vapour.

As Dick was emerging from the conning-tower, whence he had gone for the twentieth time that night in order to read the barometer, he hailed the look out. There was no necessity to go for'ard. Away on the beam, miles away it seemed, a pale gleam of light was visible beyond the horizon.

Getting his night-glasses to bear upon the spot, Tresillian saw that it was a search-light flashing intermittently at an immense distance off. Every time it shot skywards it threw into relief the outlines of a long, low-lying line of buildings.

"Surely that cannot be Nalcuanho already?" he muttered, as he dived below to rouse his comrade. Hastily springing from his bunk, Holmsby rushed up the ladder and gained the deck. For some moments he looked in the direction Dick had pointed out, till one of the crew shouted out that the light now bore dead astern. During the interval between Tresillian last sighting the beam and his reappearance on deck, the Amphibian had described an arc of 90 degrees.

Reginald's first act on spotting the light was to take its bearings with the standard compass. It bore N.E. by N., so that, making due allowance for magnetic variation, Holmsby knew that its true direction was due north.

"What do you make of it?" asked Tresillian, but Holmsby, with his night-glass glued to his eyes, silenced him by a gesture.

"K.L.V.P.—stop—V.M.C.G.B.—stop—T.Z.J.," he read. "No intelligible meaning. They're signalling in cipher. That search-light is coming from one of the warships lying off Nalcuanho Harbour."

"One of the Talpican fleet?"

"Shouldn't be surprised; but keep a bright look out. There'll be a reply from another ship shortly."

The coded message now ended, and the darkness seemed blacker than before.

Suddenly, at a distance of about a thousand feet beneath the Amphibian a vivid flash of light streamed diagonally upwards. For a few seconds the beam remained stationary, then broke into a succession of "dots and dashes."

"Silence, there!" exclaimed Holmsby sharply as some of the men began to talk in quick, excited sentences.

The Amphibian was floating almost directly over her rival, the Talpican airship.

Swiftly, yet as noiselessly as possible, the crew cleared away the quick-firers, the search-lights were screened and connected up ready to direct their penetrating beams upon the floating monster beneath.

Yet Holmsby forbore to give the order to open fire. Not from any motive of humanity: the despicable treachery that accompanied their former meeting had put Don Robiera Sanchez outside the pale. But, knowing from his previous experiences afloat, the great difficulty of hitting a source of light at a practically unknown range, the sub-lieutenant decided not to take the risk.

The next instant he regretted his decision, but it was too late to drop an explosive upon the hydrogen-charged airship. Holmsby recognised a new danger. The Talpican aircraft was running slowly dead against the wind, while the Amphibian was drifting, absolutely beyond control, straight for the path of the beam of the former's search-light. It would be useless to ascend: no matter the altitude the penetrating rays would make the grey hull of the Amphibian appear as if sheened with silver. In another half a minute—

"After gun, there—stand by. Elevate your sights to 800 metres."

Since it had to be done, Holmsby wisely decided not to wait till his gun's crew were "spotted" and dazzled by the glare of the search-light.

Now or never. With a fervent prayer for a successful shot he was on the point of giving the order to fire when the Talpican airship's search-light was suddenly screened. With a grunt of disappointment the Calderian gun-layer stood back from the night-sights and rubbed his eyes, while the captain of the guns promptly dropped the firing-key lest a spasmodic action on his part would release the charge and send it hurtling aimlessly through space.

The next five minutes was a period of anxious suspense. Holmsby could see the blinking of the distant search-light. At any moment it might cease and the Talpican airship would reply. Even in the bitterly cold air Reginald could feel the perspiration standing out in beads upon his forehead.

Then the expected flash leapt skywards, but, hurrah! far astern of the rapidly drifting Amphibian. In that five minutes the Calderian airship had passed through the normal path of her rival's search-light, and nothing short of a deliberate alteration of the powerful beam would reveal her to her antagonist.

"I'd give twelve months' seniority to know what those fellows are saying," he exclaimed. "Ten to one, Dick, they are planning a combined attack upon the forts of Nalcuanho."

But Holmsby was wrong in his surmise. The Talpican airship had notified her maritime consorts that her supply of hydrogen was getting low, and that she intended to return to the depot at San José to replenish her gas-chambers.

When the Talpican flagship again replied, Holmsby once more took a bearing.

The compass gave exactly the same bearing as previously, so that to his great satisfaction Reginald knew that the Amphibian was still keeping to the desired course, unless—an extremely improbable event—the wind had changed and was blowing in exactly the opposite direction.

Soon the flashes ceased, and Holmsby fancied that he heard the deep buzz of the airship of which they had so nearly fallen athwart; but after a further short interval the noise ceased and the Amphibian was left floating and drifting in soundless, impenetrable space.

"We may as well drop down a few thousand feet," remarked Reginald, before returning to his bunk. "There's nothing to fall foul of at two thousand: that will afford a safe margin. If nothing occurs in the meanwhile turn me out at daybreak."

At length the pale dawn glimmered in the east, and as the twilight quickly changed to day the crew of the Amphibian could determine their position. Nothing could have been better.

The crippled craft was floating in the now light breeze immediately over the city of Nalcuanho. The Talpican airship had disappeared, while seaward a haze of black smoke showed that the blockading squadron had temporarily retired in order, presumably, to replenish their coal and fuel.

"Let her come down!" exclaimed Holmsby, who had, in accordance with his instructions, been roused from his slumbers. "Bring her down on that piece of ground alongside the inner basin."

As he spoke, a puff of smoke burst from one of the batteries on the landward side of the city, and a huge rocket came soaring skywards. It struck the Amphibian on the port quarter, spluttered venomously for a few seconds, then shot earthwards. Had the Amphibian's outer skin been made of anything but asbestos-lined duralumin and had the ballonettes consisted of hydrogen or other highly-inflammable gas her destruction would have been swift and complete.

"What are those fools firing for?" asked Holmsby. "Surely the place is not in the hands of the enemy? Here, run up the ensign. They are mistaking us for the enemy."

Ere this could be done another rocket whizzed past the airship at less than ten yards' distance; but on the Calderian ensign being displayed a bugle could be distinctly heard calling the "Cease fire!"

The mistake was, under the circumstances, justifiable. The rumour that the Amphibian had been totally destroyed had already reached the capital, and the sudden appearance of an airship was interpreted as the first phase in the threatened assault by air and sea upon the forts and batteries of Nalcuanho.

Holmsby's doubts were now at rest. On all the forts the Calderian ensign was hoisted, while by means of his glasses he saw that the troops wore the light grey uniforms of the Republic.

Consummately handled, the Amphibian descended, her speed through the air now allowing the steering-rudders and elevating-planes to be brought into action, and with hardly a jolt the huge vessel was brought to earth and securely made fast in the desired mooring-ground.

It was with difficulty that the troops were able to keep back the throng of excited citizens, whose delight at the Amphibian's return was doubly increased by the good news that their President, though wounded, was once more in their midst. As soon as the lofty gangway could be rigged up and placed in position, Don Miguel was carefully lifted out on a stretcher and taken to his official residence. But before he went the promised rough drawings of the Amphibian's propelling machinery were placed in Reginald's hands.

"If these are your rough drawings I wonder what your finished plans are like, by Jove!" exclaimed Holmsby, for the draughtsmanship was beyond reproach. How a crippled and pain-racked man could produce such careful and elaborate workmanship passed his comprehension.

There was no time to be lost. If the long-threatened attack upon the capital was to be averted the Amphibian must be refitted with the least possible delay. Swarms of artisans took her in hand. The shattered plates of the submarine hull were removed, the damaged shafting and propellers were removed to serve as patterns for a new forging, while under Holmsby's personal supervision the motors were taken to a jealously-guarded workshop where the separate parts were carefully copied by the skilled mechanics. The actual assembly of the parts was to be undertaken by Holmsby and the engineer of the Amphibian.

Thanks to his training in the workshops of Osborne and Dartmouth the sub-lieutenant was well conversant with the nature of the work, and in less than a week, working at high pressure, the motors were again in position. All that remained was to wait until the extensive damage to the inner plating had been made good, a task that would take not less than another eight days, and then only if no unforeseen hitch occurred.

On the day following the completion of the reconstruction of the propelling machinery a motor-launch arrived at Nalcuanho harbour, after having made a hazardous passage from the Talpican port of San José. Her crew consisted of three Calderian mining-engineers who had been taken prisoners and sent to San José during the initial stages of the war. They had succeeded in breaking out of prison, and with the greatest audacity took possession of the motorboat and ran out of the harbour in broad daylight. Their flight was not discovered until well beyond the range of the forts and, though chased by a Talpican torpedo boat, they contrived to shake off their pursuers. They reported the Don Robiera Sanchez airship had returned to San José, having developed a leak in one of the gas-chambers, and that some days must elapse ere the craft would be ready for service.

That afternoon Holmsby strolled down to the quay in order to look at the little craft in which the prisoners had effected their escape.

It was barely twenty-four feet in length, with a sharp entry and exceptionally clean run aft. Save for a short turtle-back deck for'ard and a small space decked in aft, the boat was entirely open. Her motor, made by a well-known British firm, consisted of six cylinders developing 200 horse-power, and capable of driving her at anything between twenty and twenty-five knots.

As Holmsby looked at the little craft a thought flashed suddenly across his mind. He had an idea: the idea developed, and in less than five minutes he was making his way to the quarters of the Commandante.

CHAPTER XXIV

HOLMSBY'S RAID

General Alonzo Saldanha, the Commandante of the city of Nalcuanho and Acting-Commander-in-Chief of the Calderian army, was a short, pompous-looking man of about sixty years of age. His bronzed features, iron-grey hair and fiercely up-turned moustache gave him a very martial appearance, and in truth he was possessed of no mean military skill. But his creed was "Calderia for the Calderians," and although he was implicitly trusted by the President he harboured an intense dislike for the two Englishmen on whom Don Miguel set such store.

Nevertheless he greeted Holmsby with punctilious courtesy.

"I have just been to see the motor-boat in which the prisoners escaped," said Holmsby, "and it struck me that with a crew of determined men much could be done with her. I understand that the airship of Don Robiera Sanchez is at San José, and is very carelessly guarded. With ordinary luck it would be possible to land a few miles from the town, destroy the ship, and re-embark on the motor-launch before the enemy could realise what had happened."

"I, too, have been planning a raid into Talpican territory, Señor Holmsby," replied the Commandante, unwilling to be thought lacking in initiative. "I thought of sending half a dozen picked men by motor-car to the base of the sierras. Thence they could make their way through one of the more neglected passes, seize horses and make a dash for San José. What do you think of that?"

"They would have to go a long way from their base of operations, Commandante," observed Reginald. "And you must also take into account the difficulties occasioned by the use of wireless telegraphy and telephony in modern warfare."

"True, but for every man who can be of use in a boat we have a hundred skilled in guerrilla warfare and accustomed to making long journeys on horseback. As you are aware, our navy was not to be compared with the Talpican fleet, and now ceases to exist. In fact I know of no one capable of leading an expedition by sea. Don Carlos is, as you know, still incapacitated by wounds."

"It is my intention to ask your permission to make the attempt," said Reginald calmly.

"You!" exclaimed the Commandante, sitting bolt upright and tugging at his moustache. General Saldanha's first thought was that this young Englishman would add to his already coveted reputation should he succeed; then, on the other hand, the business would be an extremely hazardous one. The chances were that Holmsby would fall into the hands of the Talpicans, and then—but the Commandante was, after all, a soldier, and he thought it his duty to warn even the man whom he had long regarded as a dangerous rival.

"You will be shot as a filibuster if you are caught, señor," he added.

"That is a risk which I have taken into consideration, Commandante," replied Reginald. "The fact remains that with this means of offence in our possession we ought not to let a chance slip. As for the Amphibian she will not be ready for quite another week, and in the interval my companion, Mr. Tresillian, will superintend matters. So there is no reason why I should not make the attempt."

"Very well then," said General Saldanha. "I will write out an order handing over the boat to you. You may also take four men with you."

Overjoyed at his good fortune, Holmsby bade the Commandante farewell and took his leave. On returning to the Amphibian he informed Dick of what he proposed to do, steadfastly refused to let his comrade accompany him, and then set about to pick his crew. The four men he required were soon forthcoming, for Holmsby did not want to have any but those who were serving on board the airship. Fortunately two of them were conversant with the handling of a marine motor, while all, making allowances for the mercurial Calderian temperament, were to be trusted.

Before noon the motor-boat was taken out for a trial spin, and Holmsby was very well satisfied with her speed and seaworthiness. Stores, a large supply of petrol, arms and ammunition were placed on board, and everything was in readiness to make a start for San José early in the afternoon.

Holmsby had hoped to keep the object of his expedition a secret, but greatly to his annoyance the news leaked out, and before the start was made the intelligence was all over the city. This was more than annoying, for it was well known that there were spies especially amongst those of the Extremist section of the revolutionists who still remained at Nalcuanho. There was no time to be lost if the raid was to be carried out before the Talpicans heard of the departure of the daring adventurers.

At exactly two o'clock the motor-launch started on its long voyage. If all went well Holmsby hoped to arrive off the Talpican coast about an hour after sunset and reach the harbour of San José at about two in the morning. Fortunately the sea was as smooth as glass, and the boat, dashing along at twenty knots, soon began to lessen the distance betwixt her and her destination.

Presently one of the crew, who had occasion to look for something in the space under the turtle-back deck, told Reginald that there was a man lying under the folds of a tarpaulin. Unceremoniously the stowaway was hauled from his place of concealment, and Holmsby recognised him as being one of the three men who had escaped from his prison in San José.

The man was frank in his explanation. He had heard of the object of the raid, and, having a score to pay against his former captors, he meant to become a member of the expedition.

"You see, señor," he exclaimed extending his hands, palms uppermost, and shrugging his shoulders deprecatingly, "I know much of San José: therefore I am of much use to you. Moreover did not I, with my two comrades, take possession of the boat? Have I not a right to be in it?"

Holmsby was annoyed at first, but since he could not get rid of the man, who, after all, might prove of great service by his intimate knowledge of the town of San José and its vicinity, he resolved to make the best of the business.

Night succeeded day, and still the launch maintained her rapid pace through the water until an alternating red and white light appeared above the horizon.

This Holmsby knew to be the light house on the Sobra Shoal, a dangerous ledge of rocks extending seaward and for nearly a cable's length from the western side of the entrance to San José Harbour. Presently the shore lights began to loom up: the motor-boat was approaching hostile waters.

Slackening his speed to seven knots Holmsby steered the craft closer in-shore till the roar of the ground swell could be distinctly heard. This was another item in the raiders' favour since the noise of the surf drowned the pulsations of the motor.

"There is the creek we are looking for, señor," exclaimed one of the men pointing to an ill-defined gap in the white line of broken water. "It is less than twenty minutes' walk from the town."

Round swung the launch and with barely sufficient speed beyond what was required to give her steerage way she headed for the opening. Within the entrance the place appeared absolutely deserted, and Holmsby was about to congratulate himself upon this fact, when there was a dull, grinding sound. The little craft trembled from keel to gunwale, then lifted by a wave was thrown into deep water. She had bumped heavily upon a submerged rock, and ere the shore was reached it was apparent that the boat was badly damaged.

"Stuff your cap into the hole," exclaimed Reginald in a low voice, but before the seamen could raise the floor boards the water was level with the engine-bed. Nothing could stop the incoming flood; the motor gasped spasmodically, then stopped.

"We'll have to swim for it," exclaimed Holmsby. "Make sure that you have your revolvers."

As he spoke the gunwale of the waterlogged craft dipped and she sank in three feet of water. Her crew, holding their pistols well above their heads, waded ashore.

They were, indeed, in a precarious position: fifty miles from the frontier, their retreat cut off, and within a short distance of a hostile town. The Calderians looked at one another in blank despair. The sudden reverse of fortune had completely unmanned them.

"Come on, men," shouted Holmsby encouragingly. "We'll do what we can. If we are taken they can't hurt you"; but he knew full well that the Talpicans were perfectly justified in shooting him on sight—a subject of a neutral country taking up arms against a friendly state.

"Now, señor," he continued, addressing the former prisoner, who seemed fated to return to his place of incarceration, "lead the way to the spot where the airship is lying. Stand to your arms, men; but, remember, not a shot till I give the word."

Led by the mining-engineer the raiders followed in Indian file. The path from the creek ascended a steep hill that was thickly clothed with young olive trees. Here a hundred men could find shelter; but on gaining the summit of the rising ground the adventurers found themselves deprived of cover. The town of San José, now shrouded in darkness, lay beneath them.

Cautiously the six men descended the gently sloping ground. Twice they threw themselves flat upon the grass, fearing that some belated Talpican was passing that way; but their alarm was unnecessary. All was quiet.

Now they were threading their way through the narrow squalid alleys on the outskirts of the town. Well it was that the ex-captive had accompanied them, for in that maze of buildings they would otherwise have been hopelessly lost.

"Here we are, señor," whispered the guide, as the raiders halted on the edge of an open square. "The airship should be lying on our right."

"Carry on, then," replied Holmsby briefly, and treading close on one another's heels the Calderians followed their intrepid leader.

Suddenly the guide halted—so abruptly that Holmsby nearly ran into him. Peering through the darkness the Englishman could discern the figure of a sentry. The Talpican was leaning against a porch, his rifle with its long sword-bayonet held carelessly in the hollow of his arm, while, utterly unsuspecting danger, he was humming softly to himself.

Holmsby gauged the distance. Could he cover the intervening space before the man could recover from his surprise and give the alarm?

Presently the man shouldered his rifle and moved on—not, as Holmsby expected, to walk his rounds, but to shelter from the now keen wind on the other side of the porch.

Softly treading on the sand that bordered the tiled path the sub-lieutenant gained the spot where the sentry had been standing. His men followed, till the angle of the wall was inconveniently crowded.

But instead of returning, the sentry stood still. Holmsby saw a faint glimmer, followed by an impatient Caramba, while the rank smell of a South American match was drifted to his nose.

Keenly on the alert, Reginald waited till the sentry struck another match: this time with better results, for he proceeded to light a cigarette.

Blinded by the glare, the soldier was scared out of his wits to find a powerful grasp upon his neck and a heavy hand crushing the cigarette and clasping his mouth. Thinking that he had been caught by one of his officers, the man did not attempt to struggle till it was too late; in less time than one could count he was lying gagged and bound upon the ground.

Still advancing cautiously the raiders gained the side of the airship. It was not partially deflated as Holmsby expected, but was straining on its securing ropes. "Men," he whispered, "here lies our way of escape. We'll board her and cut her out."

The long bridge-like "nacelle" was within ten feet of the ground. A light was burning in the 'midships cabin, but no one was visible either on the airship or on the ground.

Swiftly the lithe Calderians clambered up the ropes. Two made their way for'ard, their keen machetes in their hands, two ran softly aft, while Holmsby and the mining-engineer, with their revolvers ready for instant use, took their stand at twenty feet from the door of the occupied cabin.

Suddenly the after part of the airship gave a sickening heave and reared itself so high in the air that Holmsby and his companion had to hold on like grim death. The stern, liberated before the bows, was tilting upwards; but the men for'ard were not much behind their comrades with their keen blades, and like a clay pigeon released from the trap the airship leapt a thousand feet in the air.

As it did so the door of the cabin opened and a man looked out. The light streaming over his shoulders fell upon the Calderian uniforms of the two seamen who had completed their work aft and had rejoined their leader. With a yell the man, ignoring Holmsby's demand to yield, sprang forward, then placing one hand on the rail surrounding the "nacelle," vaulted—not as he thought for a distance of ten feet to the ground—but into space.

"Mind, señor, there is still someone within," cautioned one of the men as Holmsby was about to explore the still lighted cabin.

"Surrender, señor: the airship is ours," shouted Reginald.

In reply a tall broad-shouldered man appeared from behind the door, and, brandishing an automatic pistol, fired rapidly and indiscriminately at the group confronting him. Holmsby felt a bullet plough through his hair, while a sharp cry behind him told him that one of the shots at least had taken effect.

Holmsby raised his revolver and pressed the trigger. The bullet struck his antagonist's automatic pistol, knocking it from his hand, and being deflected passed through the partition of the cabin; and ere the Talpican could draw his knife, Holmsby threw himself upon him.

Fiercely they struggled upon the swaying floor, until the Calderian crew, coming to the rescue, bound the still resisting man hand and foot and unceremoniously bundled him into the cabin.

Telling one of the men to guard the prisoner, Reginald made a hasty inspection of the captured craft, but no more Talpicans were found. Having found the valves regulating the supply of hydrogen, the prize crew took steps to check the still upward tendency of the airship, which had now reached an altitude of seven thousand feet. This done the propelling gear was inspected and found to be in working order, and in less than an hour the captured vessel, with her four propellers running at 500 revolutions per minute, was shaping a course towards the frontier.

Having detailed three men, one of whom had received a slight flesh wound in the shoulder, to keep the vessel on her course, and one to attend to the motors which required frequent lubrication owing to neglect on the part of the late owners to take proper care of the intricate machinery during the time the vessel was under repairs, Holmsby entered the 'midships cabin where the mining-engineer was mounting guard over the prisoner.

Now in the lamplight, Reginald recognised his captive. It was Don Robiera Sanchez, the owner of the bogus F.O. 445, the prime mover in the treacherous attacks at St. Piran's Round, at Zennor Hill, and again in the air above the sierras. The recognition was mutual, but Don Robiera, beyond giving Reginald a look of venomous hatred, said not a word; while Holmsby on his part refrained from crowing over a fallen rival. The other occupant of the car on the occasion of their first meeting was the man who had leapt to his death when the airship was boarded by the raiders.

Holmsby knew that he had no option but to hand his prisoner over to the Calderian authorities. Of his fate there could not be much doubt. Don Robiera Sanchez was a Calderian Extremist, who, not content with taking an active part in the civil war, had used his influence, only too well, to induce the Republic of Talpico to invade his country. But for him the invasion, that was all but successful, would never have taken place. As a traitor to the Republic of Calderia his doom was practically sealed.

The captured airship, the Sol d'Este, was not to be compared with the Amphibian either in speed, capability of handling, or in aggressive or defensive power. As it was, pounding against a strong hard wind, she made so little progress that daylight found her still twenty miles from the frontier.

Keeping fairly close to the ground, for Holmsby wisely decided to retain as much ballast as possible until the surmounting of the sierras had to be accomplished, the Sol d'Este presently passed above the camp of the Talpican army, for after their defeat the invaders had fallen back across the frontier until the result of the threatened sea and air attack upon Nalcuanho was known.

Thinking the airship was on her way to act in consort with the fleet, the soldiers turned out of their tents and cheered lustily. But their enthusiastic demonstrations were quickly changed into yells and shouts of execration when Holmsby, with pardonable pride, caused the Calderian ensign to be hoisted over the green and white flag of Talpico.

The troops were restrained by their officers from opening fire upon the airship; no doubt they feared the possibility of having dynamite bombs dropped amidst them, but Holmsby, finding that there was no actual hostile action, refrained from taking advantage of the powerful means of offence at his command.

It was late in the afternoon that the sentries on the batteries and forts of Nalcuanho saw the airship appearing from the south. The greatest excitement prevailed, for should the apparently hostile craft succeed in escaping the defensive fire of the rockets, the city would be at its mercy. But when the oncoming craft, flying low as if scorning the threatened fire of the batteries, was seen to display the Calderian ensign over the Talpican national flag, Nalcuanho gave itself over to unrestrained enthusiasm.

The Sol d'Este was brought to earth just beyond the outer line of defences, and Holmsby and his five comrades were received with open arms. But in the midst of these demonstrations of joy there was a certain section who bit their lips at the Englishman's unforeseen good fortune.

General Alonzo Saldanha and a few of his staff were already resolved to check the influence and popularity of Reginald Holmsby.

CHAPTER XXV

A TRAITOR'S DOOM

"How is the work progressing, Dick?" asked Holmsby, after the first greetings between the reunited pair were said.

"Better than I expected," replied Tresillian, who, clad in blue overalls and smothered with grease and dirt, looked little different from the Calderian mechanics. "We ought to have everything ship-shape again by the day after to-morrow. But what's to be done with your prize—is she going to be employed against her late owners?"

"I scarcely know. You see it's hardly my affair; but since the Sol d'Este is not a patch on the Amphibian, and is moreover a hydrogen-inflated craft, I think it would be preferable to dismantle her. Should it blow hard when she's under way she can't make headway; where she is now lying she is at the mercy of the next strong wind, while the presence of a huge bag of highly explosive gas is prejudicial to the safety of the city. I mean to point this out to the Commandante and suggest that he has the envelope deflated. At some future time, with helia ballonettes and better propelling machinery, she ought to make something of a show."

"How about that rascal Don Robiera Sanchez? What are they going to do with him?"

"I hear he's to be brought to court-martial this afternoon. Somehow or other I feel sorry for the poor brute. I almost wish it hadn't fallen to my lot to capture him. Hello, what's this?"

An orderly, bearing two official envelopes, walked up to where the two Englishmen were talking at the foot of the Amphibian's gangway, and with a salute handed one to each of the comrades.

The documents were summonses for Reginald and Dick to appear as witnesses at the forthcoming trial of Robiera Sanchez, a subject of the Republic of Calderia, on a charge of conducting traitorous correspondence with a hostile state and with taking up arms against the Republic.

"Hang it all!" exclaimed Holmsby. "Can't we manage to wriggle out of this? Surely they've enough evidence to shoot the man without dragging us into it. I'll run over and see the Commandante."

But the sub-lieutenant's mission was fruitless. General Saldanha, on the grounds of absolute necessity, refused to dispense with the evidence of the two Englishmen.

At two o'clock that afternoon the Court assembled. Even Don Miguel, carried thither on an ambulance, had to be present. Compared with a British court-martial, the trial was almost a farce. There were five judges, all of them officers of the Republican army. Altogether twelve witnesses were called for the prosecution, but no one was allowed to give evidence on behalf of the prisoner.

Don Robiera, in spite of the knowledge that the verdict was a foregone conclusion, defended himself with admirable coolness and skill, basing his plea upon the fact that when he took action against the so-called Government there was no President; consequently the constitution of the Republic of Calderia was not legal.

But when asked to explain why he attempted to harm the life and property of Don Miguel O'Rourke on British territory the prisoner merely shrugged his shoulders and stated that he had a private feud against the inventor of the Amphibian, and since the vendetta, in a modified form, was still recognised in Calderia, his action was therefore justified.

"Nothing more nor less than this—Don Miguel O'Rourke robbed me of my secret, and the Amphibian is the result of my discovery which was stolen from me."

A hush of deep amazement swept over the crowded court. Don Miguel, pale and shaking with emotion, attempted to rise, but in vain.

"If your assertion be true," continued the senior judge, "How comes it that your airship, the Sol d'Este, is admittedly inferior to the Amphibian?"

"There was neither time nor opportunity to apply my invention to that particular craft."

"Your Excellency: you hear what the man states?" asked the prosecution. "It merely requires your word on oath to give him the lie direct."

"I can safely assert that I never had any communication whatsoever with the prisoner on the subject of either his or my invention," replied Don Miguel slowly and emphatically. "I was unaware, up to this moment, that he had any pretensions with reference to scientific invention. And, above all, I cannot express myself too strongly in words that the suggestion that I robbed him of the fruits of his enterprise is utterly false."

"But I can prove it to be otherwise," stoutly asserted the prisoner. "If I may be provided with paper and ink I will write down the formulas on which the principles of Don Miguel's so-called invention are based. If Don Miguel will also write down his formulas, the two can be compared, and the truth of my assertion vindicated."

"In the interests of the Republic I cannot accede to the prisoner's request," said Don Miguel. "But if Don Robiera will, on his part, write what he has suggested, I swear by the Virgin that I will truthfully give my opinion upon the merits of the formulas."

Writing materials were thereupon handed to the prisoner, and, after scribbling vigorously for some time, he handed the paper to the President of the Court, who in turn passed it on to Don Miguel.

Holmsby, who was watching O'Rourke, particularly noticed that his face paled even more than hitherto, and his hands trembled slightly as he held the paper.

"Señors!" exclaimed Don Miguel, "only one formulas out of five has any worth. Collectively the results derived from them would be useless," and deliberately tearing the document into small pieces he thrust them into his breast-pocket.

"Rather a high-handed proceeding, Rex," whispered Tresillian, and Holmsby acquiesced with a nod.

Don Robiera, who had hitherto preserved a dignified demeanour, now burst into a torrent of expletives directed towards his rival the President of Calderia. He even tried to throw himself upon Don Miguel, but was prevented by the soldiers who were guarding him.

The rest of the trial was of the briefest description, and the anticipated verdict of guilty was followed by the sentence that the prisoner was to be shot within the walls of the prison at daybreak on the following day.

As Holmsby and his companion were leaving the court, General Saldanha beckoned to them.

"You must be present at the execution, señors," he began when the Englishmen had crossed over to where he was standing.

"Is it necessary, Commandante?"

"It is the President's wish that you should do so."

"But why 'must'?" asked Holmsby pointedly. "Supposing we refuse?"

"You are temporarily in the service of the Republic of Calderia; under what circumstances or conditions I know not, nor do I feel inclined to discuss the matter. But as servants of the State, since your presence is required, you must be present." And with the air of a man who had said what he meant to say and no more, General Saldanha turned on his heel and walked towards his quarters.

"What an old fire-eater, Rex," exclaimed Tresillian. "I suppose we must go."

"I mean to see Don Miguel first," replied Holmsby. "There are one or two questions I should very much like to ask him. They've just carried him back to his quarters, so wait here a few moments, and I'll look him up."

Holmsby had no difficulty in gaining admittance to the President's presence. Don Miguel greeted him cordially and expressed his highest admiration for the way in which Holmsby had effected his great coup.

"And it's in consequence of that business that I'm here now," said Reginald. "Now look here, Don Miguel, I've always found you straight, and I hope you have the same opinion about me. I want to ask you two questions: first, why did you tear that paper up?"

"To safeguard my interests and those of the Republic," replied Don Miguel, with a suspicion of hauteur.

"I fancy I've heard those words before," replied Reginald grimly. "To me the affair looks somewhat suspicious. Were Don Robiera's formulas similar to yours?"

"I have already sworn that they were not, Mr. Holmsby. But in confidence I may tell you that they were so near the right thing that for the moment I was on thorns. He nearly made the discovery, but one small yet important detail was omitted. You doubt me, señor?"

"Your action seemed suspicious."

"I told you that at some future date I would hand over to you my supreme secret: the formulae for the preparation of helia. My promise I mean to perform, but in the meantime I will also give you these fragments of paper. They can be easily pieced together and deciphered. When the time comes, Mr. Holmsby, for you to have my formulae you will then see that I have vindicated myself. Is that sufficient?"

Holmsby bowed.

"I hope it may be so," he replied. "No doubt Don Robiera imagined that he had a grievance and made the accusation. Now, my second question, señor: why did you order us to be present at the execution?"

"I did not order; I merely requested that you should be there."

"And why?"

"That requires an explanation. Ever since my return after the victory over the Talpicans I have had doubts as to the loyalty of the army—and the Commandante, General Alonzo Saldanha in particular. Something seems to tell me that my influence and popularity are on the wane. Tell me what is your private opinion of the Commandante?"

"Not a bad old sort as far as Calderian officials go," replied Reginald, with typical British candour. "A bit pompous, perhaps, but keen in the execution of his duties. You must be labouring under a delusion, Don Miguel. Is it likely that, with the war progressing favourably and with every prospect of success, the people wish to change their President?"

"You are not acquainted with the true Calderian temperament as I am," said O'Rourke. "In success or misfortune there is a constant desire for social upheaval. It is part of their nature. Therefore I should not be surprised if I were not shortly asked to take my departure. Fortunately I have made all preparations for that probability; but, at the same time, I still wish to retain my position. Saldanha may be a good general, but he would never make even a passable President, so I have no fears that he will supplant me. But there is one man whom I have occasion to fear as long as he remains alive: and that man is Don Robiera Sanchez. I have reason to believe that Saldanha has a secret understanding with that rogue; therefore I ask—not command—Mr. Tresillian and you, as the only persons I can implicitly trust, to see that the sentence of the court-martial is properly carried out."

"Under the circumstances I suppose we cannot refuse, although this business is not in my line, señor. But, at the same time, I hope your fears are ungrounded?"

"With Don Robiera dead my mind will be easier," replied Don Miguel.

"But mine won't," muttered Holmsby under his breath. "I feel almost responsible for the whole concern." Then aloud he added, "I will make my report at eight o'clock to-morrow, señor. At eleven, with your permission, the Amphibian starts for San José. Within a week I hope that the war will be over and all differences settled to your satisfaction. Then, having carried out our part of the compact, Mr. Tresillian and I will return home."

"Much to my regret, Mr. Holmsby."

Taking leave of the wounded President, who was still making rapid progress towards recovery, Reginald hastened back to his comrade and informed him of the reason that Don Miguel gave for wishing them to be present at the execution.

Tresillian had little sleep that night. The shadow of the tragedy weighed heavily on his mind. Holmsby, on the contrary, betrayed no emotion. He had witnessed similar spectacles in West Africa, when, during the Bangwan River Expedition, four deserters from a West African regiment were shot for taking up arms against their former comrades.

Just before sunrise the two Englishmen were aroused and, proceeding to the prison, found that the preparations for the carrying out of the sentence were already well advanced. Five feet from a blank wall in the prison-yard a grave had been dug, while at ten paces from it a dozen rifles were placed upon the ground. The Commandante with several of the staff were already present. Outside the walls a vast concourse of people had collected, filled with a morbid curiosity to hear the death-dealing volley, while many were the complaints that the good citizens of Nalcuanho had to be deprived of a spectacle which they regarded as a right to be allowed to witness.

Presently a file of soldiers, accompanied by an officer, entered and were drawn up two paces in the rear of the rifles; a drummer began beating a loud roll upon his side-drum, and escorted by two gaolers and accompanied by a priest the condemned man appeared.

He looked wonderfully self-possessed, and unhesitatingly took his place in front of the wall. A handkerchief was bound round his eyes, and his attendants retired to a safe distance.

The officer in command of the soldiers drew his sword, the men stooped, picked up their rifles and held them at the ready.

A quick word of command, the sword flashed in the air, and like a single shot the rifles delivered their volley.

Don Robiera remained standing for nearly three seconds, then, falling forwards, pitched headlong into the trench.

Without a moment's delay the Commandante shook hands with the two Englishmen, thanked them for their presence at the unavoidable incident, and escorted them to the gate.

Tresillian was shaking like a leaf. Holmsby was softly humming a tune, while his face bore a curious smile. Dick turned on him almost savagely.

"You are a callous brute, Rex."

Holmsby stopped and faced his comrade squarely.

"Dick, we can make allowances for you, but when the Commandante takes me for a greenhorn he's jolly well mistaken."

"What do you mean?"

"Mean—why Don Robiera is no more dead than you and I are. I used my eyes. The rifles did not kick: they were loaded with blank cartridges. A bullet from a modern rifle would pass clean through a man and knock chips out of the wall behind him: the plaster was not scratched. Don Miguel is right after all. That fellow Saldanha is up to some nice little game."

CHAPTER XXVI

A BLOODLESS VICTORY

At exactly eight o'clock Holmsby and his companion were ushered into the President's presence. Don Miguel's face wore an anxious look, and as Holmsby entered he could scarce control his impatience to have the expected news confirmed.

"We both saw the sentence carried out, señor," began Reginald, and a gleam of positively diabolical delight swept over O'Rourke's features. The Calderian President, in spite of his European education, still retained the fierce characteristics of his fellow-countrymen, and he listened eagerly to Holmsby's narrative.

"Now, señor," continued Reginald. "Having described to you how I carried out your request we will now discuss our plan of campaign. I take it that these gentlemen"—bowing towards a group of officials who stood by the President's couch—"will withdraw, according to custom, when matters relating to the Amphibian are broached."

The Calderian officials had no option but to retire as decorously as they could, although they were incensed at the manner in which they were compelled to give place to two aliens.

Then in a few words Holmsby told Don Miguel what his impressions were of the mock execution.

"That is what I expected, Mr. Holmsby," exclaimed the President. "The Commandante is in league with that arch-rogue Sanchez. Ere I am fit to move there will be another revolution."

"Wouldn't it be advisable for you to be taken on board the Amphibian and clear out before the storm breaks? Revolutionaries have been known to shoot their late Presidents before now."

"I would willingly, but for one reason," exclaimed Don Miguel. "As long as the Talpican army threatens our land frontiers and her fleet hovers off the capital my duty to what is undoubtedly an ungrateful country demands that I should see her through her ordeal. It is improbable—unless a serious reverse overtakes our arms—that the conspirators will take definite steps until the war is concluded."

"If I were you, señor, I would let Calderia burn her fingers."

"That I am prepared to do, should occasion arise, Mr. Holmsby; but till then my work lies in compelling Talpico to cease from her aggressions."

"Then I am at your service. Everything is prepared, and the wireless telephone is again in working order. You can rely upon it that you will be kept closely in touch with everything that takes place during the Amphibian's next cruise, and within a week you may be prepared for glorious news."

"I trust so, Mr. Holmsby," replied the President warmly, as he bade the two Englishmen adieu.

Directly the Amphibian was clear of the Calderian coast, Holmsby called the crew aft and explained to them that their President was in danger of being deposed. The men who had followed Don Miguel into exile and had loyally supported him during the construction and subsequent commission of the Amphibian were highly incensed. Some of them proposed that they should return, take Don Miguel on board, and wreak vengeance upon the Commandante; but when Holmsby explained the nature of the President's wishes they readily consented to perform their duty to their country and trust to fate to keep Don Miguel in the presidential chair.

At midnight the Amphibian was brought head to wind a thousand feet above the town of San José, and through the intense blackness of the night two powerful search-lights directed their beams upon the houses, forts, and harbour. Instantly all was confusion in the Talpican town. Fearing an irresistible onslaught from the skies, the inhabitants poured from their houses and ran for the open country; the troops manning the batteries cowered in the bomb-proof vaults or joined the civil population in their flight; while the warships, unable to cross the bar for want of sufficient tide, were huddled hopelessly together in so small a space that one of the powerful missiles from the Amphibian would have put them out of action or at any rate crippled them so severely that escape would be impossible.

By means of the international code, Holmsby flashed a message to the Governor of San José, stating in emphatic terms that if a single ship opened fire or attempted to leave the harbour the Amphibian would at once commence her work of destruction; but that if no hostile act were committed by the Talpican forces generous terms would be offered to the otherwise doomed town.

Promptly the answer was returned that San José was prepared to surrender unconditionally. For the rest of the night Holmsby was in constant telephonic communication with Nalcuanho, and an hour after daybreak the Calderian terms were presented to the Governor, who had meanwhile received authority from the President and Government of Talpico to treat on behalf of that Republic.

Don Miguel's terms were certainly moderate. They were: the surrender of one half of the effective ships of the Talpican navy; indemnity of 100,000 dollars for damage done by the Talpican army during the occupation of Calderian territory, and that a portion of the Talpican frontier, that formed a wedge into Calderia, was to be ceded to that Republic, so that the land frontier was clearly defined and strongly protected by the sierras.

Before nine o'clock Holmsby telephoned that the rough draft of the terms of peace had been signed, and asked that prize crews should be sent from Nalcuanho to man the surrendered ships. The young Englishman had good cause to feel proud of his achievements. He had won a decisive yet bloodless victory, and had secured a balance of power between the two neighbouring republics that neither would feel bold enough to disturb.

But although Holmsby patted himself on the back the news of the terms of peace was received by the populace of Nalcuanho in a manner that would have unfavourably surprised him. Once more he had under-estimated the Calderian temperament. He had imagined that since that Republic had been freed from fear of invasion, placed in possession of the nucleus of a fleet, given a slice of territory and a large sum as indemnity, national pride would be fully satisfied. But an important item in Calderian characteristics had been overlooked—revenge. Nothing short of the complete and final subjection of Talpico would satisfy the people who a few weeks ago trembled at the thunder of the Talpican guns without their gates. A bloodless victory did not appeal to their hot-tempered instincts: they wanted revenge.

For three days after the signing of the treaty of peace, Holmsby held frequent converse with President O'Rourke, but on the morning of the fourth day there was no response to Reginald's call. Whether the wireless instruments at Nalcuanho had broken down or the threatened trouble had fallen upon the ill-starred President, Holmsby knew not. He could only wait until the prize crews arrived to take possession of the ceded portion of the Talpican fleet, when he would be at liberty to take the Amphibian back to Nalcuanho.

At length the expected ships' companies arrived; but since they had left the capital before telephonic communication was interrupted they could give no further information, although Holmsby, who now shared the President's suspicions, detected a distinct aggressive manner in their replies.

It was like groping in the dark. Cut off from all communications with Calderia, Reginald was in utter ignorance of how events were trending. Nevertheless he waited until the surrendered ships, now displaying the Calderian colours, had cleared San José Harbour and were well on their way towards Nalcuanho.

He waited still longer: until the 100,000 dollars indemnity had been paid in bullion, and with this sum safely stowed on board the airship he bore away to the capital of Calderia.

It was late in the afternoon ere the Amphibian came in sight of Nalcuanho. Both Englishmen were on the promenade-deck, eagerly scanning the city through their powerful glasses.

There was something strange about the appearance of the place. The plaza and the olive-lined boulevard fronting the quay—usually the favourite places of assembly in the cool of the day of the easy-going pleasure-loving Calderians—were deserted. Most of the windows of the houses were protected by planks, while at the end of each of the broad streets converging on the quay barricades had been erected and field-guns mounted behind them. Soldiers there were in large numbers, but hardly a civilian was to be seen.

"Something has gone wrong: that's a moral cert," exclaimed Tresillian.

"Undoubtedly," replied Holmsby. "We must take necessary precautions," and raising his voice he called those of the crew who could be spared from all but the most important duties to muster aft.

In a few words he explained what he thought to be the actual state of affairs and which subsequently proved to be correct. The army, at the instigation of the Commandante, had mutinied, Don Miguel was deposed, and Don Robiera Sanchez, resurrected with dramatic effect, was literally thrust into the presidential chair. Of Don Miguel's fate there was no inkling, but the crew of the Amphibian, vowing vengeance should a hair of his head be harmed, called upon their English commander to take the Amphibian right up into the city.

In a few minutes the all-powerful airship, fully cleared for action, was floating two hundred feet above the government buildings at Nalcuanho.

CHAPTER XXVII

"I GIVE YOU ONE MINUTE TO DECIDE"

The Amphibian was indeed in a curious position. On all sides light guns for discharging either six-pounder shells or rockets were trained upon her; but two reasons prevented the rebels from proceeding to extremities: they wished to gain possession of the powerful airship in an intact condition if possible; they also feared the result of the terrific explosion of her stores of highly-charged projectiles. Yet the situation was desperate. An excitable gunner might unconsciously press the trigger of the electric pistol attached to the quick-firer; an impulsive officer without regard for the consequences, might order his men to open fire, in spite of the fact that the Calderian ensign was still displayed from the Amphibian.

Realising these possibilities Holmsby resolved to execute a daring manoeuvre, and skilfully handling the huge airship brought her to earth in the centre of the quadrangle enclosed by government offices. Here, safe from artillery fire, she lay, with barely twenty yards betwixt her bow and the windows of the Assembly Chamber. Her for'-ard quick-firer was trained point blank at that part of the buildings, while the gun's crew of the aft quick-firer brought the sights of that weapon to bear upon the offices of the Minister of War.

"Now," exclaimed Holmsby with fierce delight, for his blood was up, "we can sit tight. One single act of aggression and we'll blow the revolutionary headquarters to Hades."

He had not long to wait. Attended by several of the numerous generals of the Calderian Army the Commandante entered the quadrangle.

"Welcome to Nalcuanho once more, señor," he began. "The Republic pays tribute to your deeds of valour and discretion."

"I am sorry I cannot return the compliment, General," replied Reginald bluntly.

"My friend, you are over hasty. Since you take this tone I must call upon you in the name of the Republic to relinquish your command of the airship Amphibian."

"And if I refuse?"

"Then I must take steps to compel you."

Holmsby laughed. The little Commandante, bristling with fury, spluttered vain threats against the young Englishman; then he appealed to the crew of the Amphibian to give up their alien commander, threatening if they failed to do so, that they would all be taken prisoners and shot.

The men treated the proposal with contempt, and raised loud shouts of "Long live President Miguel."

"There is now no President Miguel," announced the Commandante. "President Robiera is now the head of the Republic. Surrender your foreign officers, men, and take the oath of allegiance to the new President, and you will have no cause to regret your actions."

"Here I stand unarmed: why do not the crew of the Amphibian accept your conditions?" demanded Holmsby calmly. "I will tell you. They will not be gulled by that rascally son of a peon the Commandante."

Stung by the insult, for General Saldanha prided himself on his direct descent from a hidalgo of Spain, the Commandante fairly danced with rage. Then turning to one of his officers he spoke a few words. A bugle blared and instantly three field-pieces were run out into the quadrangle, unlimbered and trained upon the huge bulk that overshadowed the greater portion of the confined space; while at every window commanding the Amphibian soldiers with loaded rifles simultaneously appeared.

"Have a care, men," shouted the Commandante addressing the crew of the Amphibian. "Escape is impossible. Either surrender your officers or die. I give you five minutes to decide."

Holmsby calmly took a cigarette from its case, deliberately lit it, extinguished the match, and flicked the still smouldering fragment of wood to the ground.

"Five minutes is a long time in an affair of this sort, Commandante," he said, raising his voice that all could hear him. "I, too, have something to say. Now listen: I need hardly remind you that stored within the Amphibian are explosives sufficiently powerful to destroy the whole of these buildings and shake Nalcuanho to its foundations. One shot and the trick will be done. It's a quick death, Commandante, but the thought of it is terrifying to a coward. No, don't attempt to move," for General Saldanha and several of his officers showed unmistakable signs of executing a strategic movement to the rear. "You are fairly cornered, Commandante, five rifles at least are covering you. One more step and it will be your last. Ah! That's more reasonable. Stay where you are, and it rests entirely with you how you get out of this business.

"Now I will resume my interrupted remarks. Kindly order those guns to be limbered up and those soldiers to remove their greasy-looking faces from the windows. I know you would not wish for so large an audience to witness your discomfiture. Hurry up, please, three minutes out of the five you graciously offered us are already up."

There was no help for it. The muzzles of the rifles of the Amphibian's crew formed a powerful incentive. The Commandante falteringly gave the order, the field-pieces and troops seemed to melt away, and empty windows overlooked the quadrangle.

"Now we have quite a happy family gathering," continued Reginald cheerfully, while the Calderian crew, their faith in their English commander rapidly gaining strength, began to see that Holmsby held the whip hand. "Before we proceed any further I may as well tell you how we stand. No doubt, with your born cupidity, my dear Commandante, you hoped to reap the profits of my work on Don Miguel's behalf. You may, if you behave yourself, get out of this mess unharmed. You hoped to derive some benefit from the Talpican indemnity. You won't: the whole of the 100,000 dollars is at this very moment on board the Amphibian and will be used solely for the benefit of Don Miguel and the crew who so loyally stand by him.

"That reminds me. How is Don Miguel? I hope for your sake that he has not had an—shall I call it—an accident?"

"He is no worse, Señor Holmsby," faltered the now frightened Commandante.

"Very good thing for you he isn't," replied Reginald, stepping towards a locker and extracting his revolver. "Now, General, our conversation is becoming more personal when we discuss the position of a mutual friend. If you and two of your fellow rascals will do me the doubtful honour of coming on board, we will go more into this matter."

The Commandante hesitated. Even the sight of the menacing rifles would not tempt him to put his head into the lion's jaws without a guarantee of safe conduct.

Some of his staff began to edge towards the door through which they had entered the quadrangle.

"Come back, you!" shouted Holmsby.

Most of the terrified officers stopped, but one, bending as he ran, darted towards the opening. Even as he gained the lowermost step Holmsby raised his revolver and fired. The fugitive, shot through the knee, pitched on his face.

"It's no use trying to play the fool," said Reginald sternly. "Two of you go and pick that fellow up—two of you, I said, not half a dozen—that's better. Now, General, step this way, please."

This time there could be no hesitation. The Commandante, attended by two of his gold-laced minions, ascended the rope ladder and gained the deck of the Amphibian.

"To resume our little conversation," continued Holmsby. "There is no necessity to be alarmed. If you get into an awkward predicament it is your own fault. Now, tell me, where is Don Miguel?"

"He is a prisoner in his quarters."

"And what did you intend to do with him?" asked Reginald sternly. "Shoot him? Come, speak up, and don't hesitate."

"Perhaps," mumbled the Commandante.

"It's a wonder you haven't done so already," rejoined Holmsby. "But you see we are here to shake things up a bit. Now here are pens, ink, and paper. Write an order for Don Miguel's release and give orders that the warrant is carried out."

"Don Robiera Sanchez is now the President: he alone can order Don Miguel's release," expostulated the Commandante.

"Don Robiera is the puppet and you pull the strings. I know that perfectly well. It's jolly lucky for you that Don Miguel is still alive. Do you know what would have happened had it been otherwise? From a height of six thousand feet the Amphibian would have dropped a hundred kilos of explosives on the government buildings, and the Republic of Calderia would have to look both for the fragments of her former officials and for others to take their places. But I am wandering slightly from the point, Commandante. You gave us five minutes to decide whether the crew should hand over the Amphibian to the revolutionaries. Incidentally I may mention that the five minutes have now expired and the Amphibian is still in the possession of Don Miguel's adherents. I give you one minute to decide: sign the order I require or I'll dangle you by the neck from underneath the Amphibian and at a sufficient height for every person in Nalcuanho to see. After that I'll gain my end by other means."

Without a single word in reply, General Saldanha feverishly gripped a pen, scribbled a few hasty lines, signed the paper and presented it to his conqueror.

"Thank you, Commandante; until the order is executed you must be detained here. By the bye, a polite note to President Sanchez, informing him that you are in a slight difficulty and requesting his presence, would also be in accordance with the present run of things."

"It would be of no use, señor."

"What! The performer cannot now control his puppet. Anyway, have a shot at it."

Thereupon the Commandante wrote as Holmsby had suggested, and the two letters were handed to the General's staff with instructions to carry out the orders they contained; while, under guard, the three hostages were sent for'-ard.

"By Jove, Dick!" exclaimed Reginald, when the two comrades found themselves alone. "I never talked so much in all my life. I think I must chuck the Service after this—if I am not chucked out—and go in for public speaking."

"You fairly frightened the old rascal, although I wonder you didn't mention that you knew all along that he tried to fool you over that mock execution. You see my knowledge of Spanish has increased enough for me to follow much of the conversation."

"I might have done, but I didn't want to rub it in too thick."

"If that's what you call rubbing it in lightly I should like to know how you let yourself go, Rex," replied Tresillian. "But the main thing is that it looks as if we shall rescue Don Miguel. What's going to happen next?"

"Wait and see," replied Holmsby oracularly.

CHAPTER XXVIII

DON MIGUEL'S REVENGE

Within a quarter of an hour, one of the revolutionary officers re-entered the quadrangle.

Halting at the foot of the Amphibian's ladder, he held up a sealed letter, which was taken from him by one of the crew and handed to Holmsby.

"Bring the prisoners aft," he ordered, and when the Commandante and his two companions had taken their places between the double line of the airship's crew, Holmsby opened the missive.

"I am sorry your authority has so little weight, Commandante," said Reginald. "According to this letter President Sanchez has already deemed it advisable to leave you in the lurch. The last seen of him was that he was riding as fast as his horse could carry him in the direction of Estores. Presumably he is on his way to Talpico, but I am afraid that to his surprise his reception will be totally different to his former one. I expected it would be so. However, since I've had you brought here again, you may as well wait till the second messenger returns."

But the second messenger did not return. Having played a somewhat prominent part in the latest revolution he thought it best to follow the example of President Sanchez; so having delivered the Commandante's order he rushed off to the railway station and shook the dust of Nalcuanho from his feet.

The order had the desired effect, for presently Don Miguel, carried on a stretcher, was brought into the quadrangle. The loyal crew of the Amphibian gave vent to lusty shouts of delight as they hastily prepared for the return of their idolised master, and assisted by willing hands the ex-President was hosted on to the deck of his airship.

In a few words, Holmsby informed Don Miguel of what had transpired, and learnt in return of the events that had taken place subsequent to the Amphibian's departure for San José.

It was as Holmsby had pictured. The moment the prize crews had left Nalcuanho and the revolutionary generals concluded that the indemnity had been paid, the revolution broke out. Troops seized the government buildings and threw up barricades across the principal streets. The bulk of the civil population, still favourably inclined towards President O'Rourke, came into collision with the military but were dispersed with great loss of life, and in less than an hour from the first shot the revolution became an accomplished fact.

Taken prisoner Don Miguel was confined in the city gaol. His brutal captors made no secret of the intention of the revolutionaries to shoot him as soon as the Amphibian was made to surrender. This the Commandante believed would be a comparatively easy matter, but he had learnt to his cost that he had a brave and resolute Englishman to deal with.

"Well, Don Miguel," said Holmsby, when O'Rourke had finished his narrative, "the matter rests entirely in your hands. Here is the prime mover in the revolution."

"I did not think that my confidence in you," said Don Miguel, addressing the trembling Commandante, "would have been so vilely abused. As a traitor and murderer—for at your command hundreds of the citizens of Nalcuanho have been shot down—you richly deserve to suffer the same fate as you intended to inflict upon me: there would be no mock execution, I can assure you. But although I mean to have my revenge, I give you your life. My revenge is this: I am resolved to leave Calderia for ever. She can struggle out of the throes of internal dissensions as best she may. By freeing her from foreign aggressors I have done my duty. Your punishment will be at the hands of those who will be incensed at your diabolical action in causing the benefactor of the Republic to abandon a part of his task. I wish you joy of it. Now go, and may I never see your face again."

Absolutely bewildered by this totally unexpected clemency the Commandante backed from the presence of the man whom he had so despicably served. But the crew of the Amphibian were for the first time out of hand. Throwing themselves upon the Commandante they tore the medals and decorations from his breast and trampled them on the deck; they wrenched the buttons and gold lace from his uniform; they drew his sword and broke the blade in two. Not content with this, two of the men, regardless of the risk they ran, seized the shorn general, dragged him through the War Office buildings, and presented him at a window to the dense crowd of curious and excited citizens who thronged without.

To Saldanha, the martinet, the pompous Commandante, the humiliation was almost unbearable; but he had tasted only of the first-fruits of Don Miguel's vengeance. The rest he had to suffer at the hands of the people whose confidence he had abused.

"We must do something, señor," said Holmsby, after the excitement within the quadrangle had subsided, although the tumult of the crowd without still sounded like the subdued roar of breakers on a rocky shore. "We cannot possibly stay here. What do you propose to do?"

"I have already mentioned that I have done with Calderia," replied Don Miguel. "I must find an asylum—a quiet retreat—in another country; and the one that most appeals to me is Great Britain."

"You are no stranger to it," observed Tresillian.

"No; I presume my title to Sampson's Down still holds good. I can there live in retirement and devote my days to my favourite pastime of scientific research. Fortunately I am not in want. On the contrary, I have taken care to provide against emergencies. My crew will doubtless go with me and find a home in Cornwall, but they will not suffer for their loyalty. As for the Amphibian, I mean to hand her over to the British Government as a sort of peace-offering, and, Mr. Holmsby, that act will be performed through your mediation. The secret of the preparation of helia will be entrusted into the hands of yourself and Mr. Tresillian: that alone, which ought to be worth thousands will, however, scarcely pay the debt of gratitude I owe you both. At the first opportunity on our arrival in England I will send for the necessary documents from my Paris bankers. Now Mr. Holmsby, I think I have made myself clear. If you will kindly muster the crew aft I will put my proposition before them."

Both Reginald and Dick thanked O'Rourke as well as they could find words to express their thoughts for his generosity; then Holmsby told him of the bullion he had on board.

"It affords me much satisfaction that the indemnity has not fallen into Robiera's hands," remarked Don Miguel. "Personally the money is of no particular consequence to me. If you require any of it, you have but to ask."

Both Englishmen refused, saying that Don Miguel had already been over-generous.

"Then I will divide part of it amongst the crew and devote the rest to charitable purposes," announced O'Rourke. "Now, Mr. Holmsby, if you will please do as I request you."

In less than half a minute the crew were formed up on the afterpart of the promenade-deck, and their master briefly told them of his intentions, leaving out, for the present, all mention of the proposed division of the indemnity. Without exception the men expressed their utmost willingness to follow the fortunes of their chief, and their delight was unbounded when Don Miguel completed his address by announcing that fifty thousand dollars would be divided between them. Even the noise of the crowd without was hushed into silence as the men gave three ringing shouts—the nearest approach to a hearty British cheer that Holmsby had ever heard.

"All clear fore and aft?" asked Holmsby, when the preparations for the departure were completed.

"All clear, sir," reported the quartermaster.

The engineer deftly inserted the two helia cylinders that alone were required to give the vessel the necessary buoyancy, and gracefully the Amphibian rose from the ground, and remained poised in the air at an altitude of five thousand feet. Don Miguel was carried to the rail to take a farewell glimpse of the country he wished to serve so well, then carefully handled by four of his men was taken below to his cabin.

The huge propeller began to revolve, and the Amphibian, rapidly gathering way, headed in a north-easterly direction. Upon the crowd of citizens who lined the quays of Nalcuanho a strange silence descended. Instinctively they realised that they had lost their former President for ever.

CHAPTER XXIX

HOLMSBY'S RETURN

Five days later the Amphibian sighted the Lizard. Off Rame Head she overtook the British dirigible, Gadfly, pounding against a strong east wind. It was like a motor-car overtaking a lumbering stage-coach, and even though the sight of the ensign fluttering from the Gadfly's stern filled Sub-Lieutenant Holmsby with an indescribable yearning, he could not repress his satisfaction that the Amphibian, the vessel that he was to hand over to the British Navy—was immeasurably superior to the latest production of gas-inflated dirigibles.

Without attempting to communicate, the Amphibian, with the Calderian ensign still flying, passed the British dirigible and soon left her far astern.

Off Portland the First Division of the Home Fleet, steaming in double columns, in line ahead, hove in sight. Wishing to demonstrate the manoeuvring power of the Amphibian, Holmsby brought the airship to rest upon the surface of the sea. Then diving, he steered the craft underneath the Fleet and ascended two miles in their wake.

In the gathering twilight of a dull November afternoon, Portsmouth had a momentary view of the Amphibian as she headed towards London. Then the gathering darkness hid her from further observation.

"Here we are, Dick," exclaimed Reginald, as the Amphibian descended into the vast natural hollow of the Devil's Punch Bowl, where she lay sheltered by the towering masses of Hindhead from the blustering wind. "I must ask you to stay another night on board, although the temptation to spend an evening in Town must be very great. I mean to surprise the Chief a bit. You can manage the Amphibian as well as I can, so I want you to bring her up to-morrow."

"Where to?" asked Dick.

"Let her rest on the Thames opposite the Houses of Parliament. That's about the best place I can think of. Try and get there as near as possible at eleven o'clock."

"All right, old fellow," replied Tresillian cheerfully. "But what do you propose to do?"

"Walk to Haslemere, take train to Town, and advise Admiral Pennington of the result of my investigations. I'll tell you all about it later on."

Accordingly Holmsby, clad in a thick coat in addition to his ordinary clothing—for he felt the sudden change from the warm air of Calderia to the raw atmosphere of his native land—descended the rope ladder and was soon making his way through the thick, rain-sodden gorze.

At Haslemere he had to wait for a train, but in the interval he was soon deep in the news of the day. Even during his short absence everything seemed strange: he had lost the thread of current events. But there was one paragraph that especially interested him: a report from Plymouth stating that the Gadfly had been overtaken by a mysterious airship that answered to the description of the one that caused such commotion in Cornwall in September last.

It was late in the evening when Holmsby found himself in London. His first inclination was to go to his club, but on second thoughts he decided to make for his "shore quarters" at Dulwich. But reflecting that his landlady could not be relied upon to keep the news of his return he finally decided to call upon a brother-officer, Sub-Lieutenant Diver of the Hydrographers' Department.

"Good heavens, Holmsby, is it really you?" asked that astonished officer.

"I don't think it's anyone else, George," replied Reginald. "Look here, I know you can keep a secret. I don't want a word about my being in Town mentioned until I've seen old Pennington. How did my Chief take it?"

"I hardly know, not being in the same branch. But I heard he was awfully cut up about your supposed death. Of course he had a message purporting to come from you; but not being authenticated he naturally thought it was a bogus report to throw him off the scent."

For quite two hours Holmsby related his adventures to his wonder-stricken friend. Now that the responsibility of the Amphibian was removed from his shoulders, Reginald's almost boyish character was beginning to reassert itself.

"Can you lend me your full-dress uniform, old fellow?" he asked. "I can't get mine as it is at my digs: that is if my people haven't sent for my things."

"Certainly, but what for?"

"I'm going to have a little game with old Pennington—that's all."

Shortly after nine on the following morning, Holmsby, attired in his friend's uniform, entered the offices of the Intelligence Department. Save for the messenger the place was deserted, for it was the practice of the staff to arrive just before ten.

When the head messenger had recovered from his astonishment, Holmsby impressed upon him the absolute necessity for strict official reticence and reserve concerning his presence, as he particularly wished to announce his return to the Chief in person.

But instead of going to his own room Holmsby went straight to the Chief's sanctum. It was a large apartment. A mahogany table and half a dozen arm-chairs filled the greater part of it, but immediately opposite the door was a small library, partitioned off by a heavy curtain.

Behind this curtain Holmsby took up his position. Two months previously he would not have dared to take such liberties with the much-to-be-feared Chief Director of Naval Intelligence; but emboldened by the success of his undertaking Reginald had now no fears on the point.

Precisely at ten the great man entered, but instead of following his usual custom and devoting half an hour to the daily paper, he rang his bell and asked for Captain Wapping.

"Ah! Good-morning, Wapping. I see that confounded airship has turned up again."

"Yes, sir, I saw that in last night's paper. By the description it seems to be identical with the one that poor young Holmsby lost the number of his mess over."

"Yes, unfortunately——"

At that moment the First Sea Lord burst into the room. A visit from this high and mighty one was most unusual. Captain Wapping began to back from the room. Even Holmsby's courage oozed from his finger-tips when he recognised the newcomer's bull-voice.

"Good morning, Pennington. Don't go, Wapping, this might interest you," exclaimed the First Sea Lord handing an official message to the Chief Director. "Read it, Pennington, read it aloud, so that Captain Wapping can express his opinion on it."

Thus commanded, Rear-Admiral Pennington began to read the dispatch, while the First Sea Lord, sitting cross-legged in the easiest arm-chair, drummed his finger-tips on the table in his obvious excitement.

"From Admiral commanding First Division of Home Fleet, Portland (by wireless).

"Report on 19th inst., St. Albans Head bearing NNW½W distant 12 miles, sighted airship flying Calderian colours. Airship apparently disabled, fell into sea, and sank. Detached Onyx to render assistance, but could find no trace of wreck. Eleven minutes later airship reappeared, gained an altitude of two thousand feet, and proceeded East. Request strict look out be maintained by detached units, and coastguard informed accordingly."

"Now what do you make of that? Where, by the bye is Calderia?" asked the First Sea Lord, whose geography was limited to the North Atlantic and Indian Oceans.

"Calderia, sir, is a rotten little Republic in South America. Always having revolutions, I'm told."

"I wonder if there's any truth in the newspaper report that the airship resembled the one that was reported in Cornwall in September?"

"Shouldn't be surprised, sir. The description also tallies with my late subordinate's last report—that was just before he met his death."

"Of course, I remember now. A smart young officer, I believe. Wasn't his name Holmsley?"

"Holmsby, sir; a most promising officer. His last report—I have it before me—shows wonderful powers of discernment. I took the greatest interest in his career——"

"Thank you, sir!" exclaimed Reginald.

CHAPTER XXX

THE AMPHIBIAN HAULS DOWN HER ENSIGN

"Bless my soul, it's Holmsby!" exclaimed the Rear-Admiral, while the First Sea Lord sat bolt upright in his chair, jammed a monocle to his eye, and coughed severely, until he realised that it was the much-lauded sub-lieutenant who stood before him.

"Explain yourself, Mr. Holmsby," began the Chief Director.

"I'm sorry, sir, but I did not expect to find——"

"Never mind about being sorry—that can wait. Explain how you escaped from your supposed death."

"It's a long story, sir," replied Holmsby, looking at the clock. "But I've completed my investigations."

"Carry on then, and let us hear what you've done."

Thus enjoined Holmsby began, and although his distinguished listeners followed him with rapt attention, Reginald had the greatest difficulty to keep his eyes off the clock, as the hands slowly approached the hour of eleven. Almost exactly to the minute a messenger knocked at the door and made the startling announcement that a foreign airship was on the Thames.

"On the Thames?" demanded the First Sea Lord, absolutely bewildered with the rapid chain of events.

"I think, sir, I can explain," said Holmsby.

Meanwhile the news had spread like wildfire through the various Admiralty departments. In the Accountant-General's branch half a dozen highly-paid officials were gravely deliberating whether a workman should receive threepence farthing or three-pence and three-eighths for working in a hazardous place. The conference came to an abrupt ending, and the debaters, clapping on their hats, hurried off to see the strange sight. In the Works Department an animated discussion was going on as to whether a poorly-paid clerk should receive threepence or fourpence a day increase of pay after four years' service. Here again there was a hurried exodus. It was the same with the other branches, the chiefs hurried off, and the subordinates followed at a discreet distance.

The War Office dignitaries, aroused from their slumbers, deserted their snug offices, and joined the Thames-ward throng, which had already assumed tremendous proportions.

Westminster and Lambeth bridges were packed, all vehicular traffic being suspended. Every vantage-ground on the Surrey side was crowded, while some of the more daring spectators actually invaded the sacred precincts of the terrace of the House. Even the river teemed with life, bargees reaping a rich harvest from the sightseers who were fortunate in getting standing-room in the unwieldy lighters.

Making their way across the surging tide of hurrying people the First Sea Lord, Rear-Admiral Pennington, Captain Wapping and Reginald reached the Embankment by a circuitous route, and had to walk as far as the Temple Pier before they could find a River Police launch—the only craft available.

Pushing its way betwixt the dense pack of small craft that surrounded the Amphibian, the launch ran alongside. The aircraft was floating on the swift-flowing tide, moored head and stern abreast of the Victoria Tower.

Received with naval honours by the Calderian crew, the Admiralty officials clambered up the rope ladder and gained the deck of the mysterious craft, and were introduced to the still crippled Don Miguel.

In a few well-chosen words the ex-President expressed his wish that the Amphibian should be taken over by the British nation, and on behalf of the State the First Sea Lord accepted the gift.

Thereupon the Calderian National Flag was lowered slowly from the ensign staff, and Holmsby with his own hands hoisted the White Ensign in its place.

Only one in a hundred of the spectators fully realised the meaning of this action; but a wild storm of cheering burst from the assembled throngs. The Amphibian had taken her place as the most powerful unit of the British air fleet.

Taking the discarded ensign over his arm, Holmsby returned to where Don Miguel was lying and gave it into his hands. Keenly observant, Reginald noticed that the eyes of the dapper little man were filled with tears: the sacrifice he had made was no light one. He had handed over the choicest gem of his life to the care of the foreign country that was to be his by adoption.

*****

Don Miguel, or Michael O'Rourke, as he is now called, carried out his intention and settled down in a modest country-house on Sampson's Down. There is now no mystery about his presence in the Duchy of Cornwall. He has earned the esteem of the villagers of Penkerris by his general demeanour and liberal generosity. Even Lieutenant Haslar, now in full receipt of a Greenwich Hospital pension, in addition to his well-earned Service pension, is on intimate terms with the smartly-dressed little man who walks with a decided limp—for Lieutenant Haslar has learnt that his assailants were Michael O'Rourke's foes. And the Penkerris fishermen now shoot their nets in Sampson's Cove, for the fish are not now disturbed by the movements of a mysterious object beneath the waves. Penkerris has had a "boom." Tourists flock to it in order to gaze with more than discreet curiosity upon the little man who created the Amphibian, the prototype of Britain's omnipotent air fleet—and, in consequence, Mrs. Pedler has started a select boarding-house.

A few miles from Penkerris are the spacious works of the Helia Company. Dick Tresillian had his wish, and promptly "chucked" the department for work of a more congenial nature. He is now managing-director of the Helia Company, and is reported to be rolling in money. He is a frequent and regular visitor to Sampson's Down.

As for Reginald Holmsby, he is making rapid progress in the air fleet. Already his name is high on the list for Flag rank. He, too, whenever his arduous duties permit, makes frequent visits to Sampson's Down, where, in the company of Michael O'Rourke and Dick Tresillian, he delights in recalling their adventures in the Amphibian.