said the German, in answer to the look; and he led them aft to what may be styled the quarter-deck.

“You spoke about the weight of a coat of paint on the hull just now, but I see you have planked the deck. The weight of all this planking must be something considerable,” remarked Mildmay.

“A mere trifle; it is only a thin veneering just to give a secure and comfortable foothold,” remarked the professor. He paused at what looked like a trap-door in the deck and said:

“We shall not be always soaring in the air nor groping about at the bottom of the sea; we shall sometimes be riding on the surface; and I have therefore thought it advisable to provide a couple of boats. Here is one of them.”

He stooped down, seized hold of and turned a ring in the flap, and raised the trap-door, disclosing a dark pit-like recess of considerable dimensions. Letting the flap fold back flat on the deck, the professor then stooped down and grasped the handle of a horizontal lever which lay just below the level of the deck, and drew it up into a perpendicular position, and, as he did so, a pair of davits, the upper portions of which had been plainly visible, rose through the aperture close to the protecting railing, bringing with them a handsomely modelled boat hanging from the tackles. The professor deftly turned the davits outward, and there hung the boat at the quarter in the exact position she would have occupied in an ordinary ship.

“Bravo, professor; very clever indeed!” exclaimed Mildmay. “But what is the object of those four curved tubes projecting through the boat’s bottom?”

“Those tubes,” answered the professor, “are the boat’s means of propulsion. You see,” he explained, “being built of aethereum, the boat is extremely light, and draws so little water that a screw propeller would be quite useless to her. So I have substituted those tubes instead. One pair, you will observe, points toward the stern, and one pair toward the bow. The boat’s engine is a powerful three-cylinder pump, and it sucks the water strongly in through the tubes which point forward, discharging it as powerfully out through those which point astern; thus drawing and driving the boat along at a speed of about twelve knots per hour, which is as fast, I fancy, as we shall ever want her to go. If you want to go astern the movement of a single lever reverses the whole process. There is a similar boat on the other side.”

The boat having been returned to her hiding-place, the professor next led his friends to the structure which occupied the centre of the deck. It was a perfectly plain erection, with curved sides meeting in a kind of stem and stern-post at its forward and after ends, with a curved dome-like roof, several small circular windows all round its sides, and no apparent means of entry.

“Why, how is this, professor? You have actually built your pilot-house—for such I suppose it is—without a door,” exclaimed the baronet with returning good-humour as he perceived that, even in the event of the Flying Fish failing to fly, he would still have a very wonderful ship for his money.

“As you have rightly supposed, this is the pilot-house,” answered the professor, with one hand pressing lightly against the gleaming wall of the structure. “But as to its being without a door, you are mistaken, for there it is.”

And as he spoke a door, hitherto unnoticed in the side of the building, flew open.

“Why, you are a veritable magician, professor! How on earth did you manage that?” exclaimed the colonel.

“Easily enough,” answered the professor. “Just look here, all of you. This is a secret door which it is necessary you should all know how to open. Now, there are four of us, are there not? Very well; find the fourth rivet from the bottom in the fourth row from the after end of the building—here it is—push it to your left—not press it; pressing is no good—and open flies the door. Push the rivet to the right when the door is open, and you shut it—so,” suiting the action to the word. “Now, Sir Reginald, let me see if you can open that door.”

The baronet opened and closed the door without difficulty; and then the other two essayed the attempt with similarly successful results.

“That is all right,” commented the professor. “Now step inside, please; and close the door—so: when you want to open it from the inside you simply turn this handle—so, and open it comes.”

The quartette now found themselves inside the pilothouse, which proved to be two stories in height. On their right hand they beheld the companion-way leading to the interior of the ship, with a wide flight of stairs of delightfully easy descent, handsomely carpeted, and a magnificent massive handrail and balusters of gleaming aethereum. The square opening to the companion-way was also protected by a similar handrail and balusters, producing an exceedingly rich effect and seeming to promise a corresponding sumptuousness of fitting in the saloons below.

Just clear of the head of the companion staircase and leading up one side of the pilot-house was another light staircase of open grid-work leading to the floor above, which, at a height of seven feet, spanned the building from side to side. This floor was also of light open gridwork, affording easy verbal communication between persons occupying the different stories in the pilot-house. Through this open grid-floor could be seen various apparatus, the objects of which the new-comers were naturally anxious to learn; and to this floor the professor accordingly led his companions up the staircase.

The first object to which he directed attention was a long straight bar of aethereum handsomely moulded into the form of a thick cable, and finished off at the outer end with the semblance of a “Matthew Walker” knot. This bar issued at its inner end from a handsomely panelled and moulded casing which extended down through both floors of the pilot-house, presumably covering in and protecting the mechanism with which the bar was obviously connected.

“This,” said the professor, laying his hand on the bar, “is the steering apparatus—the tiller as you call it—of the ship. It moves, as you see, in all directions, and communicates a corresponding movement to the propeller—as you may see, if you will take the trouble to look out through one of those windows.”

The trio immediately did so, and saw, as the professor had stated, that with every movement of the tiller, right or left, up or down, the propeller inclined itself at a corresponding angle. A handsome binnacle compass stood immediately in front of the tiller, but the professor did not call attention to it, rightly assuming that his companions were fully acquainted with its use and purpose.

On the professor’s right, as he stood at the tiller, was an upright lever working in a quadrant, and communicating, like the tiller—and indeed all the other apparatus—with the interior of the ship.

“This,” said the professor, directing attention to the lever, “is the lever which controls the valves of the main engines. I have fashioned and arranged it exactly like the corresponding lever in a locomotive. Placed vertically, thus, the engines remain motionless. Thrown forward, thus, the engines will turn ahead. And thrown backward, thus, they will turn astern. That is simple enough. And so is this,” directing attention to a dial on his left hand which stood facing him. The dial had a single hand which was obviously intended to travel over a carefully graduated arc of ninety degrees painted on the dial-face, and which, in addition to the graduations, was marked in the proper positions with the words “Stop;” “Quarter speed;” “Half speed;” “Full speed;” and also with two arrows pointing in opposite directions marked “On” and “Off” respectively. Just beneath the dial was a small wheel with a crank-handle projecting from one of its spokes, and on this crank-handle the