filled with machinery, surrounding a shining copper cylinder. From the outer network radiated six mighty supporting columns. These, branching as they neared the hull of the vessel, supported the power-plant and steering apparatus in the center and so strengthened the shell that the whole structure was nearly as strong as a solid steel ball. She noticed that the floor, perhaps eight feet below the center, was heavily upholstered in leather and did not seem solid; and that the same was true of the dozen or more seats—she could not call them chairs—which were built in various places. She gazed with interest at the two instrument boards, upon which flashed tiny lights and the highly-polished plate glass, condensite, and metal of many instruments, the use of which she could not guess.
After a few minutes of silence both visitors began to ask questions, and Seaton showed them the principal features of the novel craft. Crane accompanied them in silence, enjoying their pleasure, glorying in the mighty vessel. Seaton called attention to the great size and strength of the lateral supporting columns, one of which was immediately above their heads, and then led them over to the vertical column which pierced the middle of the floor. Enormous as the lateral had seemed, it appeared puny in comparison with this monster of fabricated steel. Seaton explained that the two verticals were many times stronger than the four laterals, as the center of gravity of the ship had been made lower than its geometrical center, so that the apparent motion of the vessel and therefore the power of the bar, would usually be merely vertical. Resting one hand caressingly upon the huge column, he exultantly explained that these members were "the last word in strength, made up of many separate I-beams and angles of the strongest known special steel, latticed and braced until no conceivable force could make them yield a millimeter."
"But why such strength?" asked the lawyer doubtfully. "This column alone would hold up Brooklyn Bridge."
"To hold down the power-plant, so that the bar won't tear through the ship when we cut her loose," replied Seaton. "Have you any idea how fast this bird can fly?"
"Well, I have heard you speak of traveling with the velocity of light, but that is overdrawn, isn't it?"
"Not very much. Our figures show that with this four-hundred-pound bar"—pointing to the copper cylinder in the exact center of the inner sphere—"we could develop not only the velocity of light, but an acceleration equal to that velocity, were it not for the increase in mass at high velocities, as shown by Einstein and others. We can't go very fast near the earth, of course, as the friction of the air would melt the whole works in a few minutes. Until we get out of the atmosphere our speed will be limited by the ability of steel to withstand melting by the friction of the air to somewhere in the neighborhood of four or five thousand miles per hour, but out in space we can develop any speed we wish, up to that of light as a limit."
"I studied physics a little in my youth. Wouldn't the mere force of such an acceleration as you mention flatten you on the floor and hold you there? And any sudden jar would certainly kill you."
"There can't be any sudden jar. This is a special floor, you notice. It is mounted on long, extremely heavy springs, to take up any possible jar. Also, whenever we are putting on power we won't try to stand up, our legs would crimple up like strings. We will ride securely strapped into those special seats, which are mounted the same as the floor, only a whole lot more so. As to the acceleration...."
"That word means picking up speed, doesn't it?" interrupted Dorothy.
"The rate of picking up speed," corrected Seaton. "That is, if you were going forty miles per hour one minute, and fifty the next minute, your acceleration would be ten miles per hour per minute. See? It's acceleration that makes you feel funny when you start up or down in an elevator."
"Then riding in this thing will be like starting up in an elevator so that your heart sinks into your boots and you can't breathe?"
"Yes, only worse. We will pick up speed faster and keep on doing it...."
"Seriously," interrupted the lawyer, "do you think that the human body can stand any such acceleration as that?"
"I don't know. We are going to find out, by starting out slowly and increasing our acceleration to as much as we can stand."
"I see," Vaneman replied. "But how are you going to steer her? How do you keep permanent reference points, since there are no directions in space?"
"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."
"I don't doubt it a bit, and I'm simply wild to go for a ride with you. When will you take me, Dicky?" asked Dorothy eagerly.
"Very soon, Dottie. As soon as we get her in perfect running condition. You shall be the first to ride with us, I promise you."
"Where do you cook and eat? How do you see out? How about the air and water supply? How do you keep warm, or cool, as the case may be?" asked the girl's father, as though he were cross-examining a witness.
"Shiro has a galley on the main floor, and tables fold up into the wall of the main compartment. The passengers see out by sliding back steel panels, which normally cover the windows. The pilot can see in any direction from his seat at the instrument-board, by means of special instruments, something like periscopes. The windows are made of optical glass similar to that used in the largest telescopes. They
