re one is to the Bridge, Cap'n," he said. "If you'll start in
there, sir, I'll follow up."

* * * * *

I thrust head and shoulders into the opening. Inside it was smooth
metal, with no handholds. I clawed at it trying to get farther in. The
pain stabbed at my chest.

"Cap'n, they're workin' on the door," Thomas said. "They already been at
it for a little while. We better get goin'."

"You'd better give me a push, Thomas," I said. My voice echoed hollowly
down the duct.

Thomas crowded into the chamber behind me then, lifting my legs and
pushing. I eased into the duct. The pain was not so bad now.

"Cap'n, you gotta use a special kinda crawl to get through these here
ducts," Thomas said. "You grip your hands together out in front of ya,
and then bend your elbows. When your elbows jam against the side of the
duct, you pull forward."

I tried it; it was slow, but it worked.

"Cap'n," Thomas said behind me. "We got about seven minutes now to get
up there. I set the control on the converter to start up in ten minutes.
I think we can make it O.K., and ain't nobody else comin' this way with
the converter goin'. I locked the control panel so they can't shut her
down."

That news spurred me on. With the converter in operation, the first step
in the cycle was the evacuation of the ducts to a near-perfect vacuum.
When that happened, we would die instantly with ruptured lungs; then our
dead bodies would be sucked into the chamber and broken down into useful
raw materials. I hurried.

I tried to orient myself. The duct paralleled the corridor. It would
continue in that direction for about fifteen feet, and would then turn
upward, since the Bridge was some fifteen feet above this level. I
hitched along, and felt the duct begin to trend upward.

"You'll have to get on your back here, Cap'n," Thomas said. "She widens
out on the turn."

I managed to twist over. Thomas was helping me by pushing at my feet. As
I reached a near-vertical position, I felt a metal rod under my hand.
That was a relief; I had been expecting to have to go up the last
stretch the way a mountain climber does a rock chimney, back against one
wall and feet against the other.

I hauled at the rod, and found another with my other hand. Below, Thomas
boosted me. I groped up and got another, then another. The remaining
slight slant of the duct helped. Finally my feet were on the rods. I
clung, panting. The heat in the duct