On the morrow, when I awoke after a sound sleep, our vehicle seemed motionless. It seemed to me evident that we were not running upon land. Yet neither were we rushing through or beneath the waters; nor yet soaring across the sky. Had the inventor regained that mysterious hiding-place of his, where no human being had ever set foot before him?

And now, since he had not disembarrassed himself of my presence, was his secret about to be revealed to me?

It seemed astonishing that I had slept so profoundly during most of our voyage through the air. It puzzled me and I asked if this sleep had not been caused by some drug, mixed with my last meal, the captain of the "Terror" having wished thus to prevent me from knowing the place where we landed. All that I can recall of the previous night is the terrible impression made upon me by that moment when the machine, instead of being caught in the vortex of the cataract rose under the impulse of its machinery like a bird with its huge wings beating with tremendous power!

So this machine actually fulfilled a four-fold use! It was at the same time automobile, boat, submarine, and airship. Earth, sea and air, -- it could move through all three elements! And with what power! With what speed! Al few instants sufficed to complete its marvelous transformations. The same engine drove it along all its courses! And I had been a witness of its metamorphoses! But that of which I was still ignorant, and which I could perhaps discover, was the source of the energy which drove the machine, and above all, who was the inspired inventor who, after having created it, in every detail, guided it with so much ability and audacity!

At the moment when the "Terror" rose above the Canadian Falls, I was held down against the hatchway of my cabin. The clear, moonlit evening had permitted me to note the direction taken by the air-ship. It followed the course of the river and passed the Suspension Bridge three miles below the falls. It is here that the irresistible rapids of the Niagara River begin, where the river bends sharply to descend toward Lake Ontario.

On leaving this point, I was sure that we had turned toward the east. The captain continued at the helm. I had not addressed a word to him. What good would it do? He would not have answered. I noted that the "Terror" seemed to be guided in its course through the air with surprising ease. Assuredly the roads of the air were as familiar to it as those of the seas and of the lands!

In the presence of such results, could one not understand the enormous pride of this man who proclaimed himself Master of the World? Was he not in control of a machine infinitely superior to any that had ever sprung from the hand of man, and against which men were powerless? In truth, why should he sell this marvel? Why should he accept the millions offered him? Yes, I comprehended now that absolute confidence in himself which was expressed in his every attitude. And where might not his ambition carry him, if by its own excess it mounted some day into madness!

A half hour after the "Terror" soared into the air, I had sunk into complete unconsciousness, without realizing its approach. I repeat, it must have been caused by some drug. Without doubt, our commander did not wish me to know the road he followed.

Hence I cannot say whether the aviator continued his flight through space, or whether the mariner sailed the surface of some sea or lake, or the chauffeur sped across the American roads. No recollection remains with me of what passed during that night of July thirty-first.

Now, what was to follow from this adventure? And especially concerning myself, what would be its end?

I have said that at the moment when I awoke from my strange sleep, the "Terror" seemed to me completely motionless. I could hardly be mistaken; whatever had been her method of progress, I should have felt some movement, even in the air. I lay in my berth in the cabin, where I had been shut in without knowing it, just as I had been on the preceding night which I had passed on board the "Terror" on Lake Erie.

My business now was to learn if I would be allowed to go on deck here where the machine had landed. I attempted to raise the hatchway. It was fastened.

"Ah!" said I, "am I to be kept here until the 'Terror' recommences its travels?" Was not that, indeed, the only time when escape was hopeless?

My impatience and anxiety may be appreciated. I knew not how long this halt might continue.

I had not a quarter of an hour to wait. A noise of bars being removed came to my ear. The hatchway was raised from above. A wave of light and air penetrated my cabin.

With one bound I reached the deck. My eyes in an instant swept round the horizon.

The "Terror," as I had thought, rested quiet on the ground. She was in the midst of a rocky hollow measuring from fifteen to eighteen hundred feet in circumference. A floor of yellow gravel carpeted its entire extent, unrelieved by a single tuft of herbage.

This hollow formed an almost regular oval, with its longer diameter extending north and south. As to the surrounding-wall, what was its height, what the character of its crest, I could not judge. Above us was gathered a fog so heavy, that the rays of the sun had not yet pierced it. Heavy trails of cloud drifted across the sandy floor, Doubtless the morning was still young, and this mist might later be dissolved.

It was quite cold here, although this was the first day of August. I concluded therefore that we must be far in the north, or else high above sea-level. We must still be somewhere on the New Continent; though where, it was impossible to surmise. Yet no matter how rapid our flight had been, the air-ship could not have traversed either ocean in the dozen hours since our departure from Niagara.

At this moment, I saw the captain come from an opening in the rocks, probably a grotto, at the base of this cliff hidden in the fog. Occasionally, in the mists above, appeared the shadows of huge birds. Their raucous cries were the sole interruption to the profound silence. Who knows if they were not affrighted by the arrival of this formidable, winged monster, which they could not match either in might or speed.

Everything led me to believe that it was here that the Master of the World withdrew in the intervals between his prodigious journeys. Here was the garage of his automobile; the harbor of his boat; the hangar of his air-ship.

And now the "Terror" stood motionless at the bottom of this hollow. At last I could examine her; and it looked as if her owners had no intention of preventing me. The truth is that the commander seemed to take no more notice of my presence than before. His two companions joined him, and the three did not hesitate to enter together into the grotto I had seen. What a chance to study the machine, at least its exterior! As to its inner parts, probably I should never get beyond conjecture.

In fact, except for that of my cabin, the hatchways were closed; and it would be vain for me to attempt to open them. At any rate, it might be more interesting to find out what kind of propeller drove the "Terror" in these many transformations.

I jumped to the ground and found I was left at leisure, to proceed with this first examination.

The machine was as I have said spindle-shaped. The bow was sharper than the stern. The body was of aluminium, the wings of a substance whose nature I could not determine. The body rested on four wheels, about two feet in diameter. These had pneumatic tires so thick as to assure ease of movement at any speed. Their spokes spread out like paddles or battledores; and when the "Terror" moved either on or under the water, they must have increased her pace.

These wheels were not however, the principal propeller. This consisted of two "Parsons" turbines placed on either side of the keel. Driven with extreme rapidity by the engine, they urged the boat onward in the water by twin screws, and I even questioned if they were not powerful enough to propel the machine through the air.

The chief aerial support, however, was that of the great wings, now again in repose, and folded back along the sides. Thus the theory of the "heavier than air" flying machine was employed by the inventor, a system which enabled him to dart through space with a speed probably superior to that of the largest birds.

As to the agent which set in action these various mechanisms, I repeat, it was, it could be, no other than electricity. But from what source did his batteries get their power? Had he somewhere an electric factory, to which he must return? Were the dynamos, perhaps working in one of the caverns of this hollow?

The result of my examination was that, while I could see that the machine used wheels and turbine screws and wings, I knew nothing of either its engine, nor of the force which drove it. To be sure, the discovery of this secret would be of little value to me. To employ it I must first be free. And after what I knew -- little as that really was -- the Master of the World would never release me.

There remained, it is true, the chance of escape. But would an opportunity ever present itself? If there could be none during the voyages of the "Terror," might there possibly be, while we remained in this retreat?

The first question to be solved was the location of this hollow. What communication did it have with the surrounding region? Could one only depart from it by a flying-machine? And in what part of the United States were we? Was it not reasonable to estimate, that our flight through the darkness had covered several hundred leagues?

There was one very natural hypothesis which deserved to be considered, if not actually accepted. What more natural harbor could there be for the "Terror" than the Great Eyrie? Was it too difficult a flight for our aviator to reach the summit? Could he not soar anywhere that the vultures and the eagles could? Did not that inaccessible Eyrie offer to the Master of the World just such a retreat as our police had been unable to discover, one in which he might well believe himself safe from all attacks? Moreover, the distance between Niagara Falls and this part of the Blueridge Mountains, did not exceed four hundred and fifty miles, a flight which would have been easy for the "Terror."

Yes, this idea more and more took possession of me. It crowded out a hundred other unsupported suggestions. Did not this explain the nature of the bond which existed between the Great Eyrie and the letter which I had received with our commander's initials? And the threats against me if I renewed the ascent! And the espionage to which I had been subjected! And all the phenomena of which the Great Eyrie had been the theater, were they not to be attributed to this same cause--though what lay behind the phenomena was not yet clear? Yes, the Great Eyrie! The Great Eyrie!

But since it had been impossible for me to penetrate here, would it not be equally impossible for me to get out again, except upon the "Terror?" Ah, if the mists would but lift! Perhaps I should recognize the place. What was as yet a mere hypothesis, would become a starting point to act upon.

However, since I had freedom to move about, since neither the captain nor his men paid any heed to me, I resolved to explore the hollow. The three of them were all in the grotto toward the north end of the oval. Therefore I would commence my inspection at the southern end.

Reaching the rocky wall, I skirted along its base and found it broken by many crevices; above, arose more solid rocks of that feldspar of which the chain of the Alleghanies largely consists. To what height the rock wall rose, or what was the character of its summit, was still impossible to see. I must wait until the sun had scattered the mists.

In the meantime, I continued to follow along the base of the cliff. None of its cavities seemed to extend inward to any distance. Several of them contained debris from the hand of man, bits of broken wood, heaps of dried grasses. On the ground were still to be seen the footprints that the captain and his men must have left, perhaps months before, upon the sand.

My jailers, being doubtless very busy in their cabin, did not show themselves until they had arranged and packed several large bundles. Did they purpose to carry those on board the "Terror?" And were they packing up with the intention of permanently leaving their retreat?

In half an hour my explorations were completed and I returned toward the center. Here and there were heaped up piles of ashes, bleached by weather. There were fragments of burned planks and beams; posts to which clung rusted iron-work; armatures of metal twisted by fire; all the remnants of some intricate mechanism destroyed by the flames.

Clearly at some period not very remote the hollow had been the scene of a conflagration, accidental or intentional. Naturally I connected this with the phenomena observed at the Great Eyrie, the flames which rose above the crest, the noises which had so frightened the people of Pleasant Garden and Morganton. But of what mechanisms were these the fragments, and what reason had our captain for destroying them?

At this moment I felt a breath of air; a breeze came from the east. The sky swiftly cleared. The hollow was filled with light from the rays of the sun which appeared midway between the horizon and the zenith.

A cry escaped me! The crest of the rocky wall rose a hundred feet above me. And on the eastern side was revealed that easily recognizable pinnacle, the rock like a mounting eagle. It was the same that had held the attention of Mr. Elias Smith and myself, when we had looked up at it from the outer side of the Great Eyrie.

Thus there was no further doubt. In its flight during the night the airship had covered the distance between Lake Erie and North Carolina. It was in the depth of this Eyrie that the machine had found shelter! This was the nest, worthy of the gigantic and powerful bird created by the genius of our captain! The fortress whose mighty walls none but he could scale! Perhaps even, he had discovered in the depths of some cavern, some subterranean passage by which he himself could quit the Great Eyrie, leaving the "Terror" safely sheltered within.

At last I saw it all! This explained the first letter sent me from the Great Eyrie itself with the threat of death. If we had been able to penetrate into this hollow, who knows if the secrets of the Master of the World might not have been discovered before he had been able to set them beyond our reach?

I stood there, motionless; my eyes fixed on that mounting eagle of stone, prey to a sudden, violent emotion. Whatsoever might be the consequences to myself, was it not my duty to destroy this machine, here and now, before it could resume its menacing flight of mastery across the world!

Steps approached behind me. I turned. The inventor stood by my side, and pausing looked me in the face.

I was unable to restrain myself; the words burst forth -- "The Great Eyrie! The Great Eyrie!"

"Yes, Inspector Strock."

"And you! You are the Master of the World?"

"Of that world to which I have already proved myself to be the most powerful of men."

"You!" I reiterated, stupefied with amazement.

"I," responded he, drawing himself up in all his pride, "I, Robur--Robur, the Conqueror!"