During all the hours that Sam had been in his laboratory, alone or with Alexander, I had spent most of the time with Xenora. We wandered together about the meadows, or sat in the cabin to escape the almost intolerable heat. Always I loved her more, brimming as she was with humor and sympathy and love. And bitterly I cursed the fate that was dragging us both to our doom! Even at the beginning, Sam's scientific achievements had been so far above my understanding, that I would scarcely comprehend them, and his later speculations regarding the menace of the abyss were so abstruse that I quite failed to follow them. His little workshop forward was crammed with strange machinery, some of it humming incessantly. Indeed, his apparatus was still keeping up the interference that prevented the freezing of the earth! Sam had been signally unsuccessful in getting any scientific information from Xenora, for the simple reason that she had none to impart. But, from her geographical knowledge, he attempted to draw a map, showing the locations of Lothar, of Mutron, and of the pit of the Lord of Flame. [Illustration: _The Map that Sam and Xenora Drew._] It seemed that there was a strip a score of miles in width between the farther blue walls of the abyss and the great lake we had seen. The pit of Xath seemed to be a great crater lying in that strip. On the brink of the crater Xenora located her "City of the Sleepers," or Mutron. The domain of the last city of Lothar, where she had spent her childhood, lay along the cliffs far to the west of there. Our boldest plan of action would have been to hurl the machine, by means of the rocket tubes, into the abyss in a direct attack on the Lord of Flame; but Sam, for reasons he did not divulge, doubted the success of such a maneuver. He wished to keep up his researches, and possibly to visit the city of Lothar. His apparatus told him that hidden forces were again stirring in the ether. For ten hours we moved toward the north, making a long detour to westward to keep within a valley, and always trying to take advantage of such cover as was offered by the purple trees. The country was, for the most part, rolling and green, with the great flowering trees dotting the hills and plains but sparsely. The blazing radiation of the eternal crimson day was undiminished, but the temperature fell slightly with increased altitude. Xenora and I were together at the cabin control-board, driving the machine; and Sam was in the conning-tower, with the little gun, ready for emergencies. When we had been moving for some ten hours, we mounted a low, bare hill, and saw in the little green valley before us a thicker forest of the bright purple trees, offering good cover for the machine.