f the bore and I
don't want to come down on top of one of them, even the bad one. Move
back!"

On shore, both cranes began inching up stream.

In the thundering bore, the tractor bumped against the wall of the
hole. "Hold it," Troy shouted. The carriers stopped. "Take 'er down."

Again the massive vehicle descended into the depths. The roaring
became louder with every foot and the constantly dinning noise rattled
the earphones of the crane and carrier operators. Hall stood on the
bank, his eyes glued to the thread of cable vanishing beneath the
waters.

The tractor was bumping against the wall with more violence and the
engineers could feel it tip and sway as the turbulence increased from
below.

"I think we're too close to Number Two pump," Alec yelled. "Let's get
a little more offshore." On the far bank, Number Two crane began
hauling the pulley towards him.

The undersurface bobbing lessened. "That's good, Number Two," Alec
shouted. The downward motion continued.

As suddenly as it began, the turbulence almost ceased and the sound
diminished in the black, watery hole. The big nuclear pumps stood
thirty feet high with their great jets at the top. The tractor had
descended blow the level of the jet thrust. At the same instant, there
was a forward motion and the tractor began to sweep toward the
downstream wall of the bore.

"Drop us, fast," Alec commanded. "We're being sucked."

Number One crane operator slammed his release button and the tractor
fell with a jarring crash to the floor of the catch basin. On the
floor, its mass held it in place against the drag of the three huge
pumps and the natural flow of the water.

The water was clearer and their lights penetrated a few feet into the
black-green hell around them.

"You see it?" Alec asked his partner.

"Not a thing," Troy replied, "but we can't be more than a few feet
from it. It's got to be somewhere in front of us and I think a little
to my side. The suction drag doesn't seem quite so heavy over here."

"Number One," Alec instructed, "give us a fast one-foot lift and drop
it immediately. The current will move us."

The operator took up the slack in the cable and then gave a short
burst of upwards pull and slammed the release. The tractor lifted and
was carried forward about five feet before it slammed down again and
stopped.

"There it is," Troy yelled, aiming his light to the right front of the
tractor. The beam picked out the massive casing