in my opinion the ebba could have struck no other group of islands but the bermudas in this part of the atlantic. this is clear from the distance covered from the american coast and the direction sailed in since we issued from pamlico sound. this direction has constantly been south-southeast, and the distance, judging from the ebba’s rate of speed, which has scarcely varied, is approximately seven hundred and fifty miles.

still, the schooner does not slacken speed. the count d’artigas and engineer serko remain aft, by the man at the wheel. captain spade has gone forward.

are we not going to leave this island, which appears to be isolated, to the west?

it does not seem likely, since it is still broad daylight, and the hour at which the ebba was timed to arrive.

all the sailors are drawn up on deck, awaiting orders, and boatswain effrondat is making preparations to anchor.

ere a couple of hours have passed i shall know all about it. it will be the first answer to one of the many questions that have perplexed me since the schooner put to sea.

and yet it is most unlikely that the port to which the ebba belongs is situated on one of the bermuda islands, in the middle of an english archipelago—unless the count d’artigas has kidnapped thomas roch for the british government, which i cannot believe.

i become aware that this extraordinary man is gazing at me with singular persistence. although he can have no suspicion that i am simon hart, the engineer, he must be asking himself what i think of this adventure. if warder gaydon is but a poor devil, this poor devil will manifest as much unconcern as to what is in store for him as any gentleman could—even though he were the proprietor of this queer pleasure yacht. still i am a little uneasy under his gaze.

i dare say that if the count d’artigas could guess how certain things have suddenly become clear to me, he would not hesitate to have me thrown overboard.

prudence therefore commands me to be more circumspect than ever.

without giving rise to any suspicion—even in the mind of engineer serko—i have succeeded in raising a corner of the mysterious veil, and i begin to see ahead a bit.

as the ebba draws nearer, the island, or rather islet, towards which she is speeding shows more sharply against the blue background of the sky. the sun which has passed the zenith, shines full upon the western side. the islet is isolated, or at any rate i cannot see any others of the group to which it belongs, either to north or south.

this islet, of curious contexture, resembles as near as possible a cup turned upside down, from which a fuliginous vapor arises. its summit—the bottom of the cup, if you like—is about three hundred feet above the level of the sea, and its flanks, which are steep and regular, are as bare as the sea-washed rocks at its base.

there is another peculiarity about it which must render the islet easily recognizable by mariners approaching it from the west, and this is a rock which forms a natural arch at the base of the mountain—the handle of the cup, so to speak—and through which the waves wash as freely as the sunshine passes. seen this way the islet fully justifies the name of back cup given to it.

well, i know and recognize this islet! it is situated at the extremity of the archipelago of the bermudas. it is the “reversed cup” that i had occasion to visit a few years ago—no, i am not mistaken. i then climbed over the calcareous and crooked rocks at its base on the east side. yes, it is back cup, sure enough!

had i been less self-possessed i might have uttered an exclamation of surprise—and satisfaction—which, with good reason, would have excited the attention and suspicion of the count d’artigas.

these are the circumstances under which i came to explore back cup while on a visit to bermuda.

this archipelago, which is situated about seven hundred and fifty miles from north carolina is composed of several hundred islands or islets. its centre is crossed by the sixty-fourth meridian and the thirty-second parallel. since the englishman lomer was shipwrecked and cast up there in 1609, the bermudas have belonged to the united kingdom, and in consequence the colonial population has increased to ten thousand inhabitants. it was not for its productions of cotton, coffee, indigo, and arrowroot that england annexed the group—seized it, one might say; but because it formed a splendid maritime station in that part of the ocean, and in proximity to the united states of america. possession was taken of it without any protest on the part of other powers, and bermuda is now administered by a british governor with the addition of a council and a general assembly.

the principal islands of the archipelago are called st. david, somerset, hamilton, and st. george. the latter has a free port, and the town of the same name is also the capital of the group.

the largest of these isles is not more than seventeen miles long and five wide. leaving out the medium-sized ones, there remains but an agglomeration of islets and reefs scattered over an area of twelve square leagues.

although the climate of bermuda is very healthy, very salubrious, the isles are nevertheless frightfully beaten by the heavy winter tempests of the atlantic, and their approach by navigators presents certain difficulties.

what the archipelago especially lacks are rivers and rios. however, as abundant rains fall frequently, this drawback is got over by the inhabitants, who treasure up the heaven-sent water for household and agricultural purposes. this has necessitated the construction of vast cisterns which the downfalls keep filled. these works of engineering skill justly merit the admiration they receive and do honor to the genius of man.

it was in connection with the setting up of these cisterns that i made the trip, as well as out of curiosity to inspect the fine works.

i obtained from the company of which i was the engineer in new jersey a vacation of several weeks, and embarked at new york for the bermudas.

while i was staying on hamilton island, in the vast port of southampton, an event occurred of great interest to geologists.

one day a whole flotilla of fishers, men, women and children, entered southampton harbor. for fifty years these families had lived on the east coast of back cup, where they had erected log-cabins and houses of stone. their position for carrying on their industry was an exceptionally favorable one, for the waters teem with fish all the year round, and in march and april whales abound.

nothing had hitherto occurred to disturb their tranquil existence. they were quite contented with their rough lot, which was rendered less onerous by the facility of communication with hamilton and st. george. their solid barks took cargoes of fish there, which they exchanged for the necessities of life.

why had they thus abandoned the islet with the intention, as it pretty soon appeared, of never returning to it? the reason turned out to be that they no longer considered themselves in safety there.

a couple of months previously they had been at first surprised, then alarmed, by several distinct detonations that appeared to have taken place in the interior of the mountain. at the same time smoke and flames issued from the summit—or the bottom of the reversed cup, if you like. now no one had ever suspected that the islet was of volcanic origin, or that there was a crater at the top, no one having been able to climb its sides. now, however, there could be no possible doubt that the mountain was an ancient volcano that had suddenly become active again and threatened the village with destruction.

during the ensuing two months internal rumblings and explosions continued to be heard, which were accompanied by bursts of flame from the top—especially at night. the island was shaken by the explosions—the shocks could be distinctly felt. all these phenomena were indicative of an imminent eruption, and there was no spot at the base of the mountain that could afford any protection from the rivers of lava that would inevitably pour down its smooth, steep slopes and overwhelm the village in their boiling flood. besides, the very mountain might be destroyed in the eruption.

there was nothing for the population exposed to such a dire catastrophe to do but leave. this they did. their humble lares and penates, in fact all their belongings, were loaded into the fishing-smacks, and the entire colony sought refuge in southhampton harbor.

the news that a volcano, that had presumably been smouldering for centuries at the western extremity of the group, showed signs of breaking out again, caused a sensation throughout the bermudas. but while some were terrified, the curiosity of others was aroused, mine included. the phenomenon was worth investigation, even if the simple fisher-folk had exaggerated.

back cup, which, as already stated, lies at the western extremity of the archipelago, is connected therewith by a chain of small islets and reefs, which cannot be approached from the east. being only three hundred feet in altitude, it cannot be seen either from st. george or hamilton. i joined a party of explorers and we embarked in a cutter that landed us on the island, and made our way to the abandoned village of the bermudan fishers.

the internal crackings and detonations could be plainly heard, and a sheaf of smoke was swayed by the wind at the summit.

beyond a peradventure the ancient volcano had been started again by the subterranean fire, and an eruption at any moment was to be apprehended.

in vain we attempted to climb to the mouth of the crater. the mountain sheered down at an angle of from seventy-five to eighty degrees, and its smooth, slippery sides afforded absolutely no foothold. anything more barren than this rocky freak of nature it would be difficult to conceive. only a few tufts of wild herbs were to be seen upon the whole island, and these seemed to have no raison d’être.

our explorations were therefore necessarily limited, and in view of the active symptoms of danger that manifested themselves, we could but approve the action of the villagers in abandoning the place; for we entertained no doubt that its destruction was imminent.

these were the circumstances in which i was led to visit back cup, and no one will consequently be surprised at the fact that i recognized it immediately we hove in sight of the queer structure.

no, i repeat, the count d’artigas would probably not be overpleased if he were aware that warder gaydon is perfectly acquainted with this islet, even if the ebba was to anchor there—which, as there is no port, is, to say the least, extremely improbable.

as we draw nearer, i attentively examine back cup. not one of its former inhabitants has been induced to return, and, as it is absolutely deserted, i cannot imagine why the schooner should visit the place.

perhaps, however, the count d’artigas and his companions have no intention of landing there. even though the ebba should find temporary shelter between the rocky sides of a narrow creek there is nothing to give ground to the supposition that a wealthy yachtsman would have the remotest idea of fixing upon as his residence an arid cone exposed to all the terrible tempests of the western atlantic. to live here is all very well for rustic fishermen, but not for the count d’artigas, engineer serko, captain spade and his crew.

back cup is now only half a mile off, and the seaweed thrown up on its rocky base is plainly discernible. the only living things upon it are the sea-gulls and other birds that circle in clouds around the smoking crater.

when she is only two cable’s lengths off, the schooner slackens speed, and then stops at the entrance of a sort of natural canal formed by a couple of reefs that barely rise above the water.

i wonder whether the ebba will venture to try the dangerous feat of passing through it. i do not think so. she will probably lay where she is—though why she should do so i do not know—for a few hours, and then continue her voyage towards the east.

however this may be i see no preparations in progress for dropping anchor. the anchors are suspended in their usual places, the cables have not been cleared, and no motion has been made to lower a single boat.

at this moment count d’artigas, engineer serko and captain spade go forward and perform some manoeuvre that is inexplicable to me.

i walk along the port side of the deck until i am near the foremast, and then i can see a small buoy that the sailors are hoisting in. almost immediately the water, at the same spot becomes dark and i observe a black mass rising to the surface. is it a big whale rising for air, and is the ebba in danger of being shattered by a blow from the monster’s tail?

now i understand! at last the mystery is solved. i know what was the motor that caused the schooner to go at such an extraordinary speed without sails and without a screw. her indefatigable motor is emerging from the sea, after having towed her from the coast of america to the archipelago of the bermudas. there it is, floating alongside—a submersible boat, a submarine tug, worked by a screw set in motion by the current from a battery of accumulators or powerful electric piles.

on the upper part of the long cigar-shaped iron tug is a platform in the middle of which is the “lid” by which an entrance is effected. in the fore part of the platform projects a periscope, or lookout, formed by port-holes or lenses through which an electric searchlight can throw its gleam for some distance under water in front of and on each side of the tug. now relieved of its ballast of water the boat has risen to the surface. its lid will open and fresh air will penetrate it to every part. in all probability, if it remained submerged during the day it rose at night and towed the ebba on the surface.

but if the mechanical power of the tug is produced by electricity the latter must be furnished by some manufactory where it is stored, and the means of procuring the batteries is not to be found on back cup, i suppose.

and then, why does the ebba have recourse to this submarine towing system? why is she not provided with her own means of propulsion, like other pleasure-boats?

these are things, however, upon which i have at present no leisure to ruminate.

the lid of the tug opens and several men issue on to the platform. they are the crew of this submarine boat, and captain spade has been able to communicate with them and transmit his orders as to the direction to be taken by means of electric signals connected with the tug by a wire that passes along the stem of the schooner.

engineer serko approaches me and says, pointing to the boat:

“get in.”

“get in!” i exclaim.

“yes, in the tug, and look sharp about it.”

as usual there is nothing for it but to obey. i hasten to comply with the order and clamber over the side.

at the same time thomas roch appears on deck accompanied by one of the crew. he appears to be very calm, and very indifferent too, and makes no resistance when he is lifted over and lowered into the tug. when he has been taken in, count d’artigas and engineer serko follow.

captain spade and the crew of the ebba remain behind, with the exception of four men who man the dinghy, which has been lowered. they have hold of a long hawser, with which the schooner is probably to be towed through the reef. is there then a creek in the middle of the rocks where the vessel is secure from the breakers? is this the port to which she belongs?

they row off with the hawser and make the end fast to a ring in the reef. then the crew on board haul on it and in five minutes the schooner is so completely lost to sight among the rocks that even the tip of her mast could not be seen from the sea.

who in bermuda imagines that a vessel is accustomed to lay up in this secret creek? who in america would have any idea that the rich yachtsman so well known in all the eastern ports abides in the solitude of back cup mountain?

twenty minutes later the dinghy returns with the four men towards the tug which was evidently waiting for them before proceeding—where?

they climb on board, the little boat is made fast astern, a movement is felt, the screw revolves rapidly and the tug skims along the surface to back cup, skirting the reefs to the south.

three cable’s lengths further on, another tortuous canal is seen that leads to the island. into this the tug enters. when it gets close inshore, an order is given to two men who jump out and haul the dinghy up on a narrow sandy beach out of the reach of wave or weed, and where it will be easily get-at-able when wanted.

this done the sailors return to the tug and engineer serko signs to me to go below.

a short iron ladder leads into a central cabin where various bales and packages are stored, and for which no doubt there was not room in the hold of the schooner. i am pushed into a side cabin, the door is shut upon me, and here i am once more a prisoner in profound darkness.

i recognize the cabin the moment i enter it. it is the place in which i spent so many long hours after our abduction from healthful house, and in which i was confined until well out at sea off pamlico sound.

it is evident that thomas roch has been placed in a similar compartment.

a loud noise is heard, the banging of the lid as it closes, and the tug begins to sink as the water is admitted to the tanks.

this movement is succeeded by another—a movement that impels the boat through the water.

three minutes later it stops, and i feel that we are rising to the surface again.

another noise made by the lid being raised.

the door of my cabin opens, and i rush out and clamber on to the platform.

i look around and find that the tug has penetrated to the interior of back cup mountain.

this is the mysterious retreat where count d’artigas lives with his companions—out of the world, so to speak.