The Dolphin lay, that midnight of August 10-11, awash on the surface of the Pacific some twelve hundred miles southwest of the Mexican coast. I had thought that for the time Arturo was far from Dr. Plantet’s mind. But not so. He made no move to start our voyage until for half an hour at least he had listened to the air. It was seething with world-activity--the silent echoes of our busy, modern life. But the sub-split wave-length which Arturo’s code specified, was dead. Dr. Plantet turned at last away. “Nothing there.” He spoke in matter-of-fact tone, but I could guess at the emotion it was hiding. “Nothing there--well, we must remember to try again to-morrow night.” There was in his manner what seemed to forbid discussion of Arturo. Indeed, we had much of our own concerns to busy us. We were to head, Dr. Plantet had planned, directly for the Micronesian islands. Most of the tangible evidence bearing upon the existence of a human menace, had seemed to come from that locality. The Malaysia had been lost in there, and several others of the surface freighters. And the submersible of my own line. Again, it was there that Arturo and I had seen the face in the sea; and the mermaid had been seen there. “I think,” said Dr. Plantet, “that if we are to locate this hidden enemy at all, it will be upon some of the rises in sub-sea Micronesia.” There was another factor that made him think so. For weeks he had been assembling world-data showing a disturbance of the ocean currents. With oceans receding, the water was seeping away somewhere. That the normal ocean currents were changing was unquestioned. The evidence was inconclusive, but there seemed to be an unmistakable drift toward the mid-Pacific. And Dr. Plantet thought that upon the ocean floor in Micronesia we might find evidence of the outlet. We had had, he and I, a considerable discussion on these points. “We can only try, Jeff,” he said at last. “But two thousand fathoms, even with our five hundred fathoms of additional vision, will show us no more than the mid-depth rises.” The mountain ridges. Or the great submerged plateaus; domes; volcanic sub-sea cones. But if, in the lower basins, the great caldrons or the deeps, this enemy was lurking, we would have to wait until the water materially was lowered. And that might be months, or years. We were starting from this point so comparatively near the continent because obviously it might not be in Micronesia at all that the menace lay. I had wanted to cruise the American continental shelf. Dr. Plantet would not take the time. He was convinced the danger lay farther west. But he had agreed that we should start here, and cruise across, searching as we went.