The mine layer ploughed across the sea. From time to time she heaved something overboard. Nothing seemed to happen. But each mine was, nevertheless, so adjusted that it could explode any time it touched something underwater. They did not allow the usual time so that the mine layer could get away. The mine layer had ample time, because the mines had to go slowly spinning down five long miles to the bottom of the Luzon Deep. Twenty mines went down before the first one detonated. The concussion was felt on the _Esperance_, twenty-seven thousand feet up and in shallow water. Then another, and another, and another. The mine layer continued to sow her destructive seed. Far behind her, a monstrous spouting of gas and spume rose up hundreds of feet. There was another concussion, and another.... The _Esperance_ quivered, and Terry said grimly to Deirdre, "We set off five pounds of explosive down the Deep, and the bathyscaphe returned all smashed. What will the creature do now? I wish we could get some mines down to the bottom there!" Davis came up, beaming--but shaking. "The carrier's sending some planes down to drop eggs at the spot where the fish were dragged down!" he said zestfully. Gigantic, terrifying masses of gas leaped skyward where the gases released by the exploding mines finally reached the surface. The mine layer zig-zagged, and dropped a mine. She zig-zagged again, and dropped another. Presently, she took refuge beside the carrier. The _Esperance_ drove over and came to a stop between the two armed vessels. Someone shouted down by megaphone from the carrier's deck, "What happened to you? What hit your bowsprit?" Terry shouted back, "You shot those beasts. We've been wrestling with 'em!" An enormous eruption of gas.... Then the underwater ear began to emit an unprecedented sound. It was a rushing sound, but it was only vaguely like the noise of whatever had come up from the depths last Tuesday night. This was powerful beyond imagining. "Something's coming up!" roared Terry. "Better alert for a real fight now!" Deirdre said with a little gasp, "The real creatures are coming up! Terry! The ... things that come in the bolides...." He said savagely, "They've been shaken up badly by the concussions underwater. They resented five pounds of explosive! There's been four hundred pounds in every mine! If they try to fight after what they've taken down below...." The rushing sound from underwater was a loud, throbbing hum which had no relationship with the humming sound that drove fish. Two spoutings of gas from mine-explosions shot up. There were more concussions in the water. Then something broke surface. It was huge, and looked like a rocket. It leaped. No, it dashed upward, toward the sky. It flashed skyward, accelerating as it rose. Something else broke the surface and headed for the heavens. This one was globular. There were dull concussions coming from far underwater, and more rockets broke surface and shot skyward.