The noisewhich Sweeney could now identify definitely as
that of pumps, many of themalso increased. The two men
were now walking down a long, straight corridor, bordered
by closed doors rather than maze exits; it was badly lit, but
Sweeney nevertheless allowed Rullman to get farther ahead of
him. Toward the other end of this corridor, the heat began to
diminish, to Sweeney’s relief, for he had begun to feel quite
dizzy. Rullman gave no indication that he even noticed it.
At this end Rullman ducked abruptly into a side entrance
which turned out to be the top of a flight of stone steps.
Quite a perceptible draft of warm air was blowing down it.
Warm air, Sweeney knew, was supposed to rise in a gravita-
tional field; why it should be going in the opposite direction he
could not imagine, especially since there appeared to be no
blowers in operation on this level. Since it was blowing toward
Rullman, it would also carry any noise Sweeney made ahead
of him. He tiptoed cautiously down.
Rullman was not in sight when Sweeney left the stairwell.
There was before Sweeney, instead, a long, high-ceilinged
passageway which curved gently to the right until vision was
cut off. Along the inside of the curve, regularly spaced, were
crouching machines, each one with a bank of laterally-coiled
metal tubing rearing before it. These were the sources of the
sounds Sweeney had heard.
Here, it was cold again; abnormally cold, despite the heavy
current of warm air blowing down the stab-well. Something,
Sweeney thought, was radically wrong with the behaviour of