Upward we swirled and then again, with a persistence more insensate than human, were racing downward again in a terrific swoop over the pit of the great ray! Again the deadly rays of the surrounding hundred domed forts crashed through our down-swooping fliers, sending masses of them again into whirling wreckage, while as we swooped down over the pit and upward again in that lightning-like rush through death we saw that our rays had missed once more and that none of the control-boxes had this time been destroyed by them! And as we reeled upward again over the great pit, from over the giant domed forts, we saw that but a few more than five hundred space-fliers remained to us of the thousand and more with which we had first flashed downward! In three downward swoops only, in three lightning-like moments of attack, the giant invulnerable forts beneath had annihilated more than half our force, and we had succeeded in destroying but a single one of the twenty control-boxes! "The end!" cried Whitely. "The end of our chance to halt the great sun-ray!" "The end of our great fight through the solar system--the end of Earth's and the solar system's last chance!" For it was the end! Even as we cried out thus we knew it, beyond shadow of doubt, as the shattered mass of our remaining space-fliers reeled high above Triton's roof, high above the great pit of the ray and the colossal moving domed forts that guarded it! Marlin--Whitely--Randall--they were swaying in that moment, the knowledge of doom plain upon their faces as upon mine! Another great swoop downward and those giant, almost invulnerable moving forts would blast us entirely from the air with their storms of rays! All of the nineteen remaining controls below must be destroyed to halt the mighty sun-ray, and before we could destroy even one of them, we would be annihilated! The giant ray beside us would turn the sun on ever faster, turn it on until in a score more days the sun would divide at last into a double star and engulf its planets in its diverging fires--all save Neptune! And as we came thus to the end at last of our superhuman struggle to halt the solar system's doom there was coming up to us from beneath the great roof of Triton a vast, rolling muffled shouting of triumphant Neptunians, of all the Neptunian hordes upon Triton who saw as we did that for us the end had come! "But if it's the end, we'll meet it trying!" Randall cried. "One more swoop downward--we can die that way at least----!" * * * * * But from Marlin, who stood with crimson face and blazing eyes, there came a mad shout. "The end--_no_!" he cried. "_There's still a chance for us--to halt the other ray--the ray on Triton's outward side!_"