"The air is absolutely motionless," said the professor. "No more favourable moment could possibly have been chosen for the difficult task of moving the _Flying Fish_ out of her present cramped quarters, and we will at once avail ourselves of it. Lieutenant, I will ask you to return here presently on the `look-out,' as you sailors term it. Your duty will be to see that when we move out of the shed we do not come into collision with anything. Perhaps you, colonel, will kindly go to the other end the deck, also on the `look-out;' and, as for you, Sir Reginald, I must ask you to stand on the deck just outside the pilothouse, to see that the electric lamp on the top of it does not come into collision with the roof-timbers, and so drag the roof off the shed. But as it is necessary that you should all become acquainted with the working of the ship, you had better be with me in the pilot-house until we are actually ready to move." "Now," continued the professor when the quartette had made their way to the upper floor of the pilot-house, which was moderately illuminated by an electric lamp of small power, "the first thing to be done is to place the tiller of the ship in a horizontal position, and thus bring into action the automatic balancing gear. So! It is done. The next thing is to expel the air from the entire hull of the ship, excepting, of course, the comparatively insignificant portion reserved for habitation, and this I do by injecting vapour into the several compartments. The vapour drives out the air, and then, condensing like steam, creates, if required, a perfect vacuum. This large wheel controls the valve which we now want to open. I turn it this way, so--and now we shall see what will happen." Two large dials were attached to the side of the pilothouse, close together; and upon these the professor now intently fixed his gaze. The index-hands of both were seen to be moving. A period of perhaps half a minute elapsed, and then the professor, suddenly shutting off the vapour, went over and closely inspected both dials. "Good!" he exclaimed, after a single keen glance at each of them. "Gentlemen, let us congratulate each other. Our experiment is a SIGNAL SUCCESS!" "How do you know that, professor? How can you tell?" eagerly asked his companions.