ned bin, and with
it all deadly radioactive material near him. This was the equipment that
must have been used to handle the dud atom bomb some months back. It had
been ready for that. It was ready for this emergency. Somebody had tried
to think of every imaginable situation that could arise in connection
with the Platform.

But in a moment a guard came for Joe and took him to where the Chief and
Haney and Mike waited by the still incompletely-pulled-away crates. They
had some new ideas about the job on hand that were better than the
original ones in some details. All four of them set to work to make a
careful survey of damage--of parts that would have to be replaced and of
those that needed to be repaired. The discoveries they made would have
appalled Joe earlier. Now he merely made notes of parts necessary to be
replaced by new ones that could be had within the repair time for
rebalancing the rotors.

"This is sure a mess," said Haney mournfully, as they worked. "It's two
days just getting things cleaned up!"

The Chief eyed the rotors. There were two of them, great four-foot disks
with extraordinary short and stubby shafts that were brought to
beautifully polished conical ends to fit in the bearings. The bearings
were hollowed to fit the shaft ends, but they were intricately scored to
form oil channels. In operation, a very special silicone oil would be
pumped into the bearings under high pressure. Distributed by the
channels, the oil would form a film that by its pressure would hold the
cone end of the bearing away from actual contact with the metal. The
rotors, in fact, would be floated in oil just as the high-speed
centrifuge the Chief had mentioned had floated on compressed air. But
they had to be perfectly balanced, because any imbalance would make the
shaft pierce the oil film and touch the metal of the bearing--and when a
shaft is turning at 40,000 r.p.m. it is not good for it to touch
anything. Shaft and bearing would burn white-hot in fractions of a
second and there would be several devils to pay.

"We've got to spin it in a lathe," said the Chief profoundly, "to hold
the chucks. The chucks have got to be these same bearings, because
nothing else will stand the speed. And we got to cut out the bed plate
of any lathe we find. Hm. We got to do our spinning with the shaft lined
up with the earth's axis, too."

Mike nodded wisely, and Joe knew he'd pointed that out. It was true
enough. A high-speed gyro co