n disappeared; and as it disappeared the shielding wall began to give
way. It did not cave in abruptly, but softened locally, sagging into a
peculiar grouping of valleys and ridges--contesting stubbornly every
inch of position lost. And gray Roger knew that the planetoid was
doomed. His supposedly impregnable screen was failing in spite of its
utmost measure of energy, and, that defense down, the citadel would not
last a minute. Therefore he summoned a chosen few of his motley crew of
renegade scientists and issued brief instructions. For minutes a host of
robots toiled mightily, then a portion of the shield bulged out,
extended into a tube beyond the attacking layers of force, and from it
there erupted a beam of violence incredible. A beam behind which was
every volt and ampere that the gigantic generators and accumulators of
the planetoid could yield. A beam that tore screamingly through the
ether; that by the very vehemence of its incalculable energy tore a hole
through the redly impenetrable Nevian field and hurled itself upon the
inner screen of the fish-shaped cruiser in frenzied incandescence. And
was there, or was there not, a lesser eruption upon the other side--an
almost imperceptible flash, as though something had shot from the doomed
planetoid out into space?

Nerado's looped neck straightened convulsively as his tortured drivers
whined and shrieked at the terrific overload; but Roger's effort was far
too intense to be long maintained. Even before his accumulators failed,
generator after generator burned out, the defensive screen collapsed,
and the red converter beam attacked voraciously the unresisting metal of
those prodigious walls. Soon there was a terrific explosion as the
pent-up air of the planetoid broke through its weakening container, and
the sluggish river of allotropic iron flowed in an ever larger stream,
ever faster.

"It is well that we had an unlimited supply of iron." Nerado tied a knot
in his neck and spoke in huge relief. "With but the seven pounds
remaining of our original supply, I fear that it would have been
difficult to parry that last thrust."

"Difficult?" asked the second in command. "We would now be swimming in
space. But what shall I do with this iron? Our reservoirs will not hold
it all."

"Seal up one or two of the lower storage compartments, to make room for
this lot. Immediately it is loaded, we return to Nevia. There we shall
install reservoirs in all the spare space, an