“Bigger than a man’s body?” Than said.
“No, hardly. Maybe as big through as a man’s head, at the
most.”
“Won’t work,” Than said tersely. “I tried it. You can’t lead
a bubble through a pipe that small. As Lavon says, it clings
to the inside of the tube and won’t be budged unless you put
pressure behind itlots of pressure. If we build this ship,
we’ll just have to abandon it once we hit our new world;
we won’t be able to set it down anywhere.”
“That’s out of the question,” Lavon said at once. “Putting
aside for the moment the waste involved, we may have to use
the ship again in a hurry. Who knows what the new world will
be like? We’re going to have to be able to leave it again if it
turns out to be impossible to live in.”
“Which is your model, Than?” Shar said.
“This one. With this design, we do the trip the hard way
crawl along the Bottom until it meets the sky, crawl until
we hit the next world, and crawl wherever we’re going when
we get there. No aquabatics. She’s treadmill-powered, like
Tanol’s, but not necessarily man-powered; I’ve been thinking
a bit about using motile diatoms. She steers by varying the
power on one side or the other. For fine steering we can also
hitch a pair of thongs to opposite ends of the rear axle and
swivel her that way.”
Shar looked closely at the tube-shaped model and pushed
it experimentally along the table a little way. “I like that,” he
said presently. “It sits still when you want it to. With Than’s
spherical ship, we’d be at the mercy of any stray current at
home or in the new worldand for all I know there may be