ame 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