There came at last, however, the night of the 16th, the night of our start, with the space-flier complete and ready in its framework at last. The last work of Marlin and Whitely had been to check over the construction-plans of the flier, which were to be left behind so that a great fleet of space-fliers, as the World President had said, could be constructed. Were we to return from Neptune with knowledge of the position and nature of the great doom-ray's source there, that fleet of space-fliers would be ready to sally out and attempt to bring an end to the great ray. But that knowledge, if we gained it, we must bring back ourselves, since there was no method of communication from our space-flier to Earth, the well-known "Heaviside layer" surrounding Earth being impenetrable to all radio and communication vibrations and making such communication impossible. With this last preparation completed, however, we four stood ready upon the night of the 16th for the start of our great venture. * * * * * It was an hour after midnight that we were to start, and it was not until some minutes past midnight that Marlin and Whitely and Randall and I left our quarters in the World Government building and ascended to its roof. As we emerged upon that roof we stopped involuntarily. For the great roof itself and all the surrounding colossal city of New York were lit now with brilliant white suspended lights, and beneath them upon the roof and in the streets far beneath were masses upon masses of waiting men and women. Those upon the roof were the twelve hundred members of the great World Congress, assembled there to see our start out into the void on our desperate venture. At their center was a clear, roped-off space on the roof in which there towered the framework that held our great space-flier, gleaming in the brilliance of the lights about it, and just inside that clear space stood the World President, a half-dozen officials beside him.