One of them held the dissembled parts of the great cogged mechanisms we had seen them taking down and storing inside the cylinders. Another two or three sections held similar dissembled parts of differing machines that had evidently been taken from another part of the dead vast compartment-city beneath. We passed up through sections that held supplies and strange tank-like affairs, that seemed not unlike the batteries of our own space-flier, and then were climbing up into the topmost section of the cylinder. This was a section whose top and walls were set with so many windows as to make its sides seem quite transparent. And this topmost section, in which a pair of Neptunians already were standing, was quite apparently the control-section. For at its center rose from its floor a thick metal pillar or standard, upon the top and sides of which were set a battery of dozens of small green studs, and around this were strange seats in which the two waiting Neptunians were now taking their places. As Marlin and I climbed into that uppermost section, the guards and the leader of the disk-bodied Neptunians behind us, we gazed wonderingly about, at the central control-standard and at the strange graduated scales with moving dots of light upon them, that were set here and there in the walls and that seemed recording instruments of one kind or another. Then the crimson-marked leader had given utterance to another sharp succession of snapping sounds, a swift command, at the same time motioning us to the side of the circular room, where were similar low, strange seats. In these we seated ourselves, the four Neptunians who watched us taking places on either side of us, and then as the leader took the remaining seat at the control-standard, we saw one of the other two seated there reach forth with strange quick limbs and touch a number of the studs in swift succession. At once the great throbbing of the generators or mechanisms in the cylinder's lowest section intensified, and as Marlin and I gazed quickly outward through the windows about us we saw that now the other cylinders in the compartment were all closed and throbbing like this one. Then, as one of the Neptunians at the control-standard touched another stud, the cylinder in which we were rose swiftly upward and out of the great black-walled compartment, rose up smoothly over the dead compartment-city into the pale light of the Neptunian day, followed at once by the three other cylinders. The dim day about us was already waning, fading, as night crept across this huge world of silence and death, with its ceaseless rotation, but there remained still enough light for us to see far across the mighty maze of compartments that was the deserted and dead city. And now across that city the four cylinders were rushing, racing over it in horizontal position, the strange seats upon which we and the Neptunians were seated swinging in gimbal-like frameworks as the cylinder swung thus from vertical to horizontal.