cting tube. On the third
try, the cap descended over the open end of the tube, effectively
shielding the radioactive source material in the gauge. Once the cap
was in place, Alec moved up to the gauge and put a lock clamp on the
cap and then picked up the gauge and moved back up the ramp.

The wind was screaming across the top of the slot in the snow pack as
he pushed the device over the edge and then heaved himself out into
the teeth of the storm.

He could barely make out the form of Troy fifty feet east of the
original position of the gauge. The tall engineer had taken the
replacement gauge from his pack and was positioning it into the snow
on the surface of the snow pack. The replacement was bulkier than the
defective unit and it was different in design.

This was a combination radiation-sonar measuring gauge. Placed on top
of an existing snow field, its sonar system kept account of the snow
beneath the gauge to the surface of the soil; the radiation counter
metered the fresh snow that fell on it after it was placed in
position. The two readings were electronically added and fed into the
transducer for automatic transmission.

Troy hollowed out a slight depression in the fresh snow and pressed
the gauge into the hollow, then packed the snow back around it to keep
it from being shifted by the high velocity winds until fresh snows
buried it. Satisfied that it was properly set, he removed the
radiation cap lock and slipped his ski pole through the ring on the
cap. He backed away, lifted the cap from the gauge and then quickly
moved out of the area.

Alec had stowed the bad gauge in his pack and removed a pressure
pillow gauge to put into the deep hole in the snow. The man-cut chasm
would serve as a partial gauge hole and, from a purely research point
of view, it would be interesting to know how much snow would drift and
fall back into the hole. The pressure pillow contained a quantity of
antifreeze solution and some air space. As the snow fell upon the
pillow and piled up, its weight would press down and the pressure upon
the pillow would be measured by instruments and again relayed to a
small transmitter for reading back at Spokane. The pillows were used
in many flat open areas where snow pack was uniform across a large
level surface.

The pillow in place, Alec again climbed from the chasm and was locking
on his skis when Troy slid up. The ice-dry snow was driving almost
horizontally across the face of the rid