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, Adlington his allotropic-iron atomic bombs, Spencer his indestructible armor-piercing projectiles, and Dutton his shatterable flasks of the quintessence of corrosion--a sticky, tacky liquid of such dire potency that only one rare Solarian element could contain it. Ten, twenty, fifty, a hundred were thrown as fast as the automatic machinery could launch them; and the Nevians found them adversaries not to be despised. Size for size, their screens were quite as capable as those of the _Boise_. The Nevians' destructive rays glanced harmlessly from their shields, and the Nevians' elaborate screens, neutralized at impact by those of the torpedoes, were impotent to impede their progress. Each projectile must needs be caught and crushed individually by beams of the most prodigious power; and while one was being annihilated dozens more were rushing to the attack. Then while the twisting, dodging invader was busiest with the tiny but relentless destroyers, Rodebush launched his heaviest weapon. The macro-beams! Prodigious streamers of bluish-green flame which tore savagely through course after course of Nevian screen! Malevolent fangs, driven with such power and velocity that they were biting into the very walls of the enemy vessel before the amphibians knew that their defensive shells of force had been punctured! And the emergency screens of the invaders were equally futile. Course after course was sent out, only to flare viciously through the spectrum and to go black.