cond in this red field. And
watch out for a violet field pretty soon--it'll be worse than this. We
can handle them alone, I think; but if we can't, there's nothing in the
System that can help us!"

And now the hitherto passive screen of the super-ship became active. At
first invisible, it began to glow in fierce violet light, and as the
glow brightened to unbearable intensity the entire spherical shield
began to increase in size. Driven outward from the super-ship as a
center, its advancing surface of seething energy consumed the crimson
murk as a billow of blast-furnace heat consumes the cloud of snowflakes
in the air above its cupola. Nor was the red death-mist all that was
consumed. Between that ravening surface and the armor skin of the
_Boise_ there was nothing. No debris, no atmosphere, no vapor, no single
atom of material substance--the first time in Terrestrial experience
that an absolute vacuum had ever been attained!

Stubbornly contesting every foot of way lost, the Nevian fog retreated
before the violet sphere of nothingness. Back and back it fell,
disappearing altogether from all space as the violet tide engulfed the
enemy vessel; but the flying fish did not disappear. Her triple screens
flashed into furiously incandescent splendor and she entered unscathed
that vacuous sphere, which collapsed instantly into an enormously
elongated ellipsoid, at each focus a madly warring ship of space.

Then in that tube of vacuum was waged a spectacular duel of
ultra-weapons--weapons impotent in air, but deadly in empty space.
Beams, rays, and rods of Titanic power smote crackingly against
ultra-screens equally capable. Time after time each contestant ran the
gamut of the spectrum with his every available ultra-force, only to find
all channels closed. For minutes the terrible struggle went on, then:

"Cooper, Adlington, Spencer, Dutton!" Rodebush called into his
transmitter. "Ready? Can't touch him on the ultra, so I'm going onto the
macro-bands. Give him everything you have as soon as I collapse the
violet. Go!"

At the word the violet barrier went down, and with a crash as of a
disrupting Universe the atmosphere rushed into the void. And through the
hurricane there shot out the deadliest material weapons of Triplanetary.
Torpedoes--non-ferrous, ultra-screened, beam-dirigible torpedoes charged
with the most effective forms of material destruction known to man.
Cooper hurled his canisters of penetrating gas, Adlingto