oon-shadows within range of
his vision did not stir.

He nosed the beetle carefully up to the heap. He had no equipment for
moving those tons of soil and rock, but that was no matter. He twisted a
knob on the control panel, a shutter in the beetle's forward cowling
snapped open and a telescoping drill thrust from its housing, chattered
briefly and took hold, while the engine's pulse strengthened to take up
the load.

Twice Dworn abandoned fruitless borings and tried a different spot. On
the third try, at almost full extension the drill-point screeched
suddenly on metal and then as suddenly met no more resistance. Dworn
switched on the pump, and quickly turned it off again; he swung the
overhead hatch open, and--pausing to listen warily once more--clambered
out onto the cowling, in the cold night air, to open the sample tap at
the base of the drill and sniff the colorless fluid that trickled from
it.

It gave off the potent odor of good fuel, and Dworn nodded to himself,
not regretting his caution though in this case it had not been needed.
But--clever caterpillars had been known to bury canisters of water in
their caches, poison for the unsuspecting.

* * * * *

The pump throbbed again; there was the satisfying gurgle of fuel flowing
into almost-empty tanks. Dworn leaned back, seizing the opportunity to
relax for a moment in preparation for the strenuous journey still
before him.

But he didn't fail to snap alert when just as the gauge trembled near
the full mark, he heard pebbles rattling on the hillside above.
Immediately thereupon he became aware of the grind of steel on stone and
the rumbling of an imperfectly muffled engine.

In one smooth rapid motion Dworn switched off the pump, and spun the
drill control. As the mechanism telescoped back into place, he gunned
his engine, and the beetle shot backward and spun round to face the
oncoming noise.

A squarish black silhouette loomed high on the slope above the
overhanging bank, which rose so steeply that a stone loosened by turning
treads bounded with a clang off the beetle's armor in the wash below.
The caterpillar halted momentarily, engine grumbling to take in the
scene.

Dworn didn't linger to learn its reaction at spying a looter. A snap
shot from his turret gun exploded directly in front of the other
machine, throwing up a cloud of dust and--he hoped--confusing its crew.
And the beetle was fleeing around the bend in th