For but a moment we crouched there, then raised ourselves and looked quickly around us. Cylinders were moving to and fro from time to time over the compartments of the twilight band, from the sunward side, and we knew that if we remained upon the wall's top long we would inevitably be discovered. We must descend into one of the compartments as swiftly as possible. But into which one? In an endeavor to solve the question, we began to crawl quietly along the top of the wall, gazing down upon its other side as we did so. The compartment on that other side was a cell like our own, and it was empty; but its only egress was into the hall between the cell-rows, and that was guarded by the Neptunian armed guards. To descend into it or into any of the other compartment-cells was useless, so along the wall's top we crawled, through the dusk, until in a moment or so more we found ourselves looking down into one of the irregular-shaped ante-rooms to the great circular compartment of the Council of Thirty. * * * * * In the ante-room compartment stood the usual files of Neptunian guards, and as we saw them, far beneath us, we heard a sharp staccato order from one of them, saw them standing aside from the entrance to the great circular Council compartment. Then, as we watched, we saw emerging from that circular compartment in a moment more, thirty Neptunians, the supreme Council of Thirty before which we had been so short a time before! They were conversing now in their staccato speech, no longer held silent by the synthesizing of their minds in the great globe-mechanism, and as we watched them from far above, we saw them, surrounded now by the files of guards, passing across the ante-room compartment and through a door in it, toward the sunward side of Triton. When they had gone, the ante-room compartment empty beneath us, Marlin pointed downward. "Down here, Hunt!" he whispered. "If we stay longer on the wall-tops we'll be seen by some cylinder passing above, and if we get down into this compartment, we can make our way to the dark side!" "You're going to try to steal a cylinder on the dark side?" I asked, and he nodded. "Yes, in the darkness there, where the Neptunians are sleeping, we'll have a chance to get at one. But we must hurry, for there's little time left before the great signal comes for those on dark and sunward sides to change places!"