!"

In a moment more the Jovian plane of force was launched, the powerful
ray-screens flared into white-hot, sparkling defense, and the battle was
on. Held spell-bound as the castaways were by that spectacular duel, yet
Stevens' trained mind warned him of the perils of their position.

"Grab your bow and we'll beat it!" and he rapidly led her away from the
steel structures to an open hillside, well away from any projection,
tree, or sharp point of rock. "If that keeps up very long, we're going
to see some real fireworks, and I don't know whether there will be
enough left of our plant here to salvage or not. Everything is grounded,
of course, but I don't believe that ordinary grounds will amount to much
against what's coming."

"What _are_ you talking about?" demanded Nadia.

"Look!" he replied, pointing, and as he spoke, a terrific bolt of
lightning launched itself from the incandescent screen of the Jovian
vessel upon their slender ultra-radio tower, which subsided instantly
into a confused mass of molten and twisted metal.

* * * * *

As the power of the beams was increased and as the combatants drew
nearer and nearer the ground, the lightning display grew ever more
violent. Well below the canyon as the warring vessels were, the
power-plant and penstock did not suffer at all and only a few discharges
struck the _Forlorn Hope_--discharges which were carried easily to
ground by the enormous thickness of her armor--but every prominent
object for hundreds of yards below the _Hope_ was literally blasted out
of existence. Radio tower, directors and fittings; trees, shrubs, sharp
points of rock--all were struck again and again; fused, destroyed,
utterly obliterated by the inconceivable energy being dissipated by
those impregnable screens of force. Even almost flat upon the ground as
the spectators were, each individual hair upon their heads strove
fiercely to stand erect, so heavily charged was the very air. Stevens'
arm was blue for days, such was Nadia's grip upon it, and she herself
could scarcely breathe in that mighty arm's constriction--but each was
conscious only of that incredibly violent struggle, of that duel to the
death being waged there before their eyes with those frightful weapons,
hitherto unknown to man. They saw the _Sirius_ triumphant, and Stevens
led the dancing girl back into their dwelling of steel.

"Danger's all over now. Radio's gone, but we should fret a lot abo