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?