"To that end we shall sink a shaft here; and, far enough underground to be secure against detection, we shall drive a tunnel to the field from which the space-fleet is to take its departure. We ten thinkers shall go, accompanied by four hundred of you doers, who are to bore the way and to perform such other duties as may from time to time arise. We shall return in due time. Our special instruments will prevent us from falling into the sun. During our absence allow no human to live who may by any chance learn of our presence here. And do not make any offensive move, however slight, until we return." * * * * * Efficiently, a shaft was sunk and the disintegrator corps began to drive the long tunnel. And along that hellish thoroughfare, through its searing heat, its raging back-blast of disintegrator-gas, the little army of robots moved steadily and relentlessly forward at an even speed of five miles per hour. On and on, each intelligent mechanism energized by its own tight beam from the power-plant. [Illustration: _Efficiently, a shaft was sunk and the disintegrator corps began to drive the long tunnel._] And through that blasting, withering inferno of frightful heat and of noxious vapor, in which no human life could have existed for a single minute, there rolled easily along upon massive wheels a close-coupled, flat-bodied truck. Upon this the ten thinkers constructed, as calmly undisturbed as though in the peace and quiet of a research laboratory, a domed and towering mechanism of coils, condensers, and fields of force--a mechanism equipped with hundreds of universally-mounted telescopic projectors. On and on the procession moved, day after day; to pause finally beneath the field upon which Earth's stupendous armada lay. The truck of thinkers moved to the fore and its occupants surveyed briefly the terrain so far above them. Then, while the ten leaders continued working as one machine, the doers waited. Waited while the immense Terrestrial Fleet was provisioned and manned; waited while it went through its seemingly interminable series of preliminary maneuvers; waited with the calmly placid immobility, the utterly inhuman patience of the machine. Finally the last inspection of the gigantic space-fleet was made. The massive air-lock doors were sealed. The field, tortured and scarred by the raving blasts of energy that had so many times hurled upward the stupendous masses of those towering superdreadnaughts of the void, was deserted. All was in readiness for the final take-off. Then, deep underground, from the hundreds of telescopelike projectors studding the domed mechanism of the automatons, there reached out invisible but potent beams of force.