"Better drop a few cans down on that dome, fellows, before they make trouble for us," suggested Rodebush to his gunners. "We can't," came Adlington's instant reply. "We've been trying it, but that's a polycyclic screen. Can you drill it? If you can, I've got a real bomb here--that special we built--that will do the trick if you can protect it from their beams until it gets down into the water." "I'll try it," Cleveland answered, at a nod from the physicist. "I couldn't drill Nerado's polycyclics, but I couldn't use any momentum on him. Couldn't ram him--he fell back with my thrust. But that screen down there can't back off, so maybe I can work on it. Get your special ready, and hang on, everybody!" The _Boise_ looped upward, and from an altitude of miles dove downward through a storm of force-balls, rays, and shells; a dive checked abruptly as the hollow tube of energy, which was Cleveland's drill, snarled savagely down ahead of her and struck the shielding hemisphere with a grinding, lightning-splitting shock. As it struck, backed by all the enormous momentum of the plunging space-ship and driven by the full power of her mightiest generators, it bored in, clawing and gouging viciously through the tissue of that rigid and unyielding barrier of pure energy. Then, mighty drill and plunging mass against iron-driven wall, eye-tearing and furiously spectacular warfare was waged. Well it was for Triplanetary, that day, that its super ship carried ample supply of allotropic iron; well it was that her originally Gargantuan converters and generators had been doubled and quadrupled in power on the long Nevian way! For that oven-girdled fortress was powered to withstand any conceivable assault; but the _Boise_'s power and momentum were now inconceivable, and every watt and every dyne was solidly behind that hellishly flaming, that voraciously tearing, that irresistibly ravening cylinder of energy incredible! Through the Nevian shield that cylinder gnawed its frightful way, and down its protecting length there drove Adlington's "Special" bomb. "Special" it was indeed; so great of girth that it could barely pass through the central orifice of Ten's mighty projector, so heavily charged with sensitized atomic iron that its detonation upon any planet would not have been considered for an instant if that planet's integrity meant anything to its attackers. Down the shielding pipe of force the "Special" screamed under full propulsion, and beneath the surface of Nevia's ocean it plunged. "Cut!" yelled Adlington, and as the scintillating drill expired, the bomber snapped his detonating switch.