"That was our hardest problem," explained Seaton, "but Martin solved it perfectly. See the power-plant up there? Notice those big supporting rings and bearings? Well, the power-plant is entirely separate from the ship, as it is inside that inner sphere, about which the outer sphere and the ship itself are free to revolve in any direction. No matter how much the ship rolls and pitches, as she is bound to do every time we come near enough to any star or planet to be influenced by its gravitation, the bar stays where it is pointed. Those six big jackets in the outer sphere, on the six sides of the bar, cover six pairs of gyroscope wheels, weighing several tons each, turning at a terrific speed in a vacuum. The gyroscopes keep the whole outer sphere in exactly the same position as long as they are kept turning, and afford us not only permanent planes of reference, but also a solid foundation in those planes which can be used in pointing the bar. The bar can be turned instantly to any direction whatever by special electrical instruments on the boards. You see, the outer sphere stays immovably fixed in that position, with the bar at liberty to turn in any direction inside it, and the ship at liberty to do the same thing outside it. "Now we will show you where we sleep," Seaton continued. "We have eight rooms, four below and four above," leading the way to a narrow, steep steel stairway and down into a very narrow hall, from either side of which two doors opened. "This is my room, the adjoining one is Mart's. Shiro sleeps across the hall. The rest of the rooms are for our guests on future trips." Sliding back the door, he switched on the light and revealed a small but fully-appointed bedroom, completely furnished with everything necessary, yet everything condensed into the least possible space. The floor, like the one above, was of cushioned leather supported by springs. The bed was a modification of the special seats already referred to. Opening another sliding door, he showed them an equally complete and equally compact bathroom. "You see, we have all the comforts of home. This bathroom, however, is practical only when we have some force downward, either gravitation or our own acceleration. The same reasoning accounts for the hand-rails you see everywhere on board. Drifting in space, you know, there is no weight, and you can't walk; you must pull yourself around. If you tried to take a step you would bounce up and hit the ceiling, and stay there. That is why the ceilings are so well padded. And if you tried to wash your face you would throw water all over the place, and it would float around in the air instead of falling to the floor. As long as we can walk we can use the bathroom--if I should want to wash my face while we are drifting, I just press this button here, and the pilot will put on enough acceleration to make the correct use of water possible. There are a lot of surprising things about a trip into space."