What could be the meaning of this other colossal force-ray, of equal size and power, going out into the vast void outside the solar system? The first great ray that was shooting toward the sun and turning the sun ever faster--its purpose was at least comprehensible, but what purpose could there be in sending an opposite and equal ray out into the mighty void from Triton's other side? That was the question that whirled in my astounded brain in that moment as the eleven cylinders shot on toward that second great ray, over Triton's metal surface. Marlin, though, on seeing that second great ray, seemed to be less puzzled than before. It seemed to have solved for him some problem which the sight of the first huge ray had suggested. To me it was utterly incomprehensible, and perplexed and awed I watched that huge pale ray and the vast pit from which it sprang as we raced toward them. I saw that on that pit's curving walls there jutted forth a score of cube-like projections or control-rooms similar to those in the pit of the first ray. Then I forgot pit and rays alike as the cylinder in which we were and all those behind it slowed suddenly in mid-air and then dipped sharply downward. * * * * * Down and down they shot, toward the vast gleaming metal roof of great Triton; down, until we saw that just beneath us there was outlined in that roof a great circle, slightly sunken. Toward this the cylinders dropped, and then as they came to a pause just above it I saw that set beside that circle in the roof was a transparent section beneath which was a small cage-like room, brightly lit. In this were a half-dozen Neptunians, and as they saw the eleven cylinders dropping and pausing above the circle in the roof they turned swiftly, pressed what seemed a series of knobs in their cage-room, and at once the great sunken circle beneath us was sliding along beneath the roof to one side, sliding smoothly away and leaving thus beneath us a great circular opening in the roof.