Slowly the net ascended until it was out of sight and only the occasional blinking of the fish's light lit up the path he was taking to the outside world. Then even this died out. "A good haul," said Amos Fearless, in the sign language. "Now for that ray of fire and our day's work will be done. And I will be glad of it." "So will I be glad," answered Dave. "We'll want several days down here in order to get used to deep-sea work once more." The diving bell was supplied with a second net--smaller and of a much tighter mesh, and this they now put out in the hope of catching one of the rays of fire. Two were in the vicinity and eying the bell and those inside with much curiosity. "Nasty, snaky-looking things," observed Dave, as he helped to bait the net. "And they look wicked, too." "All of the deep-sea fish are wicked-looking," was the answer. "I never saw anything different." They waited for fully ten minutes before one of the strange fishes came up to the net. Then it darted inside and began biting at the bait. "We've got him!" cried Dave, and began to pull on the string which shut the net up. At once the ray of fire tried to escape. But it was too late, for the top of the net closed tight just as he shoved his nose against it. Then an odd thing happened. The fish began to lash around in a circle, emitting a strange sound like the roll of distant thunder. Sparks flew from its tail which dropped down into the water like the sparks from a Roman candle. "What a beautiful sight!" began Dave, when of a sudden he heard a swishing through the water. He turned, to behold his father in a truly perilous situation. The second ray of fire had come up and wound itself around Amos Fearless' neck. Its hard body was like a wand of rubber, and unless the fish were released the old diver would speedily be strangled to death! CHAPTER XXV LEFT TO PERISH For one moment Dave Fearless' heart seemed to stop beating. The sight before him was a terrible one. Vainly was his father struggling to free himself from the deadly embrace of the creature which had attacked him. There were three coils of the ray of fire around the old diver's neck and these were slowly but surely choking the life out of the man. His eyes were bulging from their sockets--his tongue stuck from his mouth. In a few seconds more all would be over. Close at hand stuck a knife in a case on the wall of the diving bell. With a leap Dave secured the blade. Another leap and he was at his parent's side. But how should he attack the strange, snake-like fish? A false cut and he might stab his father in the throat. But he must act, or it would be too late. With a cautious movement of the knife he slit the fish along the back. There was a strange hissing and the ray of fire swung loose the end of its tail. It caught Dave around the wrist, holding that member as in a vise.