It had, indeed, been a period of tense and toiling activity for Marlin and Whitely and Randall and me, that time of four weeks that had elapsed since Marlin had proposed his great plan to the World Congress. In those weeks all our efforts, and all the efforts of the world too, it seemed, had been concentrated upon the building of that space-flier in which we four, first of all men, were to venture out into the great void, to flash out to Neptune in our attempt to halt the great ray that was spinning our sun ever faster to its destruction and to ours. For each day of those four weeks the rotatory speed of the sun had grown ever greater, its rotatory period decreasing by an exact four hours each day. The instruments of Dr. Whitely, too, showed that the mighty force-ray was still playing unceasingly from Neptune upon the turning sun's edge, spinning that sun ever faster. Already the terrific pressure of that great ray had lowered the sun's rotatory period to 18 days, 4 hours, and in hardly more than a hundred days more, we knew, would have brought the sun's rotatory period down to that critical figure of one hour at which it could no longer hold together, at which it would divide into a double star and plunge Earth to doom and wreck the solar system. And with that knowledge, all the world had sought to aid in the construction of our space-flier. Dr. Marlin had directed that construction, aided by his assistant, young Randall, whom I had met for the first time and had found a sunny-haired fun-loving fellow of my own age. And it had been Dr. Marlin who, after consultation with the world's greatest engineering authorities, had chosen for the flier the form of a great polyhedron. Such a form, it had been found, could resist pressure from within and without much better than the spherical form that had been at first suggested, and it was realized that this power of resistance would be necessary. For upon venturing out from Earth's gravitation-field into gravitationless space, the very interior stresses of such a space-flier would tend to explode it unless it was braced against those stresses. Also the space-flier was to be shot out through the void and maneuvered in that void by the pushing reaction of its own great force-rays against the Earth or other planets, and though that force would thus hurtle the flier out at terrific speed, it would also crumple the flier itself unless it were strong enough to withstand the force-ray's terrific pressure. * * * * *