rojectors may be mighty useful, too."

On and on the savages came, massed in formations showing some signs of
rude discipline. This time there was neither shrieking nor yelling; the
weird creatures advanced silently and methodically. Here and there were
massed groups of hundreds, dragging behind them engines which Stevens
studied with interest.

"Hm ... m ... m. Catapults," he mused. "You were right, girl of my
dreams--armor and bows and arrows wouldn't help us much right now.
They're going to throw rocks at us that'll have both mass and momentum.
With those things they can cave in our side-armor, and might even dent
our roof. When one of those projectiles hits, we want to know where it
ain't, that's all."

Stevens cast off the heavily-insulated plug connecting the power plant
leads to his now almost fully charged accumulators, strapped himself and
Nadia into place at the controls, and waited, staring into the plate.
Catapult after catapult was dragged to the lip of the little canyon,
until six of them bore upon the target. The huge stranded springs of
hair, fiber, and sinew were wound up to the limit, and enormous masses
of rock were toilsomely rolled upon the platforms. Each "gunner" seized
his trip, and as the leader shrieked his signal the six ponderous masses
of metalliferous rock heaved into the air as one. But they did not
strike their objective, for as the signal was given, Stevens shot
power into his projectors. The "Forlorn Hope" leaped out of the canyon
and high into the air over the open meadow, just as the six great
projectiles crashed into the ground upon the spot which, an instant
before, she had occupied.

* * * * *

Rudimentary discipline forgotten, the horde rushed down into the canyon
and the valley, in full clamor of their barbaric urgings. Horns and
arms tossed fiercely, savage noises rent the air, and arrows splintered
harmlessly upon steel plate an the mystified and maddened warriors upon
the plain below gave vent to their outraged feelings.

"Look, Nadia! A whole gang of them are smelling around that power plug.
Pretty soon somebody's going to touch a hot spot, and when he does,
we'll cut loose on the rest of them."

The huge insulating plug, housing the ends of the three great cables
leading to the converters of the turbo-alternator, lay innocently upon
the ground, its three yawning holes invitingly open to savage arms. The
chief, who had been inspecting th