Forward of the living-room, and near what corresponded to the bow of the projectile, were the sleeping-rooms, consisting of two long, narrow compartments, with a passageway between them, like the aisle in a sleeping-car. The beds were berths against the wall, much as in the Pullman cars of to-day. In the very "nose" of the Annihilator was the pilot house. Here were grouped together the wheels, levers, cams, gears, pistons and other apparatus that controlled the big projectile. Standing in it, and peering out through a heavy plate glass window, the operator could guide the machine in any direction he desired, and he could also regulate the rate of progress. A number of scientific instruments were carried, for showing and registering the speed and direction of the Annihilator, the distance it was above the earth, and there was an indicator to note how near the travelers came to Mars. There was also a powerful telescope, and a number of cameras so arranged that they would automatically take pictures. "We'll have to travel through space pretty fast in order to cover thirty-five millions of miles," observed Jack, stopping in his work of helping rivet some of the plates. "About how fast will we have to go, Mr. Roumann?" "I have it all figured out," replied the German. "I hope our projectile will stand it," remarked Mr. Henderson. "We did not have to make such terrific speed on our other voyages." "I think that the Annihilator, as we have planned it, will not suffer from the strain of speed," when on Mr. Roumann, looking up from his study of some blue-prints. "You may be astonished when I tell you we shall have to travel at the rate of one hundred miles a second." "One hundred miles a second!" exclaimed Jack. "That's pretty fast, isn't it?" "It's at the rate of eight million six hundred and forty thousand miles a day," came from Mark, who was a rapid figurer. "And to cover thirty-five million miles would take us less than five days," said Jack. "But such an enormous speed--" "We must travel at about that speed," interrupted Mr. Roumann, "though I fancy we will be nearer ten days than five in reaching Mars." "Why?" asked Jack. "Because we will not dare travel at such terrific speed as one hundred miles a second through the atmosphere of the earth. We would be burned into cinders by the mere friction of the air. Therefore, I shall send the Annihilator comparatively slowly through the earth's atmosphere, and perhaps I will find that I shall have to do the same thing when we near Mars. But while traveling through the ether, or the space that is between the two can go as fast as we like, which will as Mark has said, eight million miles per day." "But even that rate," began Jack, "is going to pretty fast." "It is faster than almost anything except light," went on Mr. Roumann.