For two days, now, we had been flashing with that great fleet behind us from Earth, out toward the solar system's edge on our mighty expedition, and five days had passed since we had stood before the World Congress with Marlin rendering to it our report. In those intervening three days on Earth we had been the center of such a whirl of hectic activity as the world had never known before--the whirl of preparations for the start of the colossal fleet. For in those three short days Marlin with the energies of a world at his bidding, had strained every nerve to complete the last preparations of the great armada of space-fliers which he, with us three as his lieutenants, was to lead out on its unprecedented flight to Neptune. The most necessary preparation was the equipping of the five thousand space-fliers with the concentrated force-ray weapons used by the Neptunians in their space-cylinders, those concentrated rays which, instead of pushing against what they struck, tore through it with driving power. Fortunately, the production of these concentrated rays required only the addition of special smaller ray-openings beside the regular ray-openings in the sides of the space-fliers, but even so it strained the capacities of the world's workers to install in each of the space-fliers those smaller openings in the short time available. Each of the five thousand space-fliers held a crew of eight, their operators having been trained during our absence as fast as the fliers themselves had been built. We four in our own space-flier, the flagship of the great fleet, had four additional crew-members now, four mechanic-operators who worked in shifts and tended ceaselessly the operation of the flier's various mechanisms, the great generators, and the other mechanical equipment, thus leaving Marlin and Randall and Whitely and myself free to devote all our attention to the command of the great fleet itself, though one of us retained the controls of the flier itself. Another preparation that had been made during our absence had been to equip each flier with space-walkers for its crew, and to equip each with efficient radiophone apparatus. This, while the Heaviside layer around Earth would prevent it functioning from Earth to space or from space to Earth, would allow free communication from space-flier to space-flier while in space itself, and thus would allow Marlin and us to control with spoken orders all the great fleet we led.