"Cameras," said Deirdre. "Mounted on rifle stocks, with flashbulbs in the reflectors. You aim, pull the trigger, and the shutter opens as the flashbulb goes off. So you get a picture of whatever you aim at, night or day."
"Why ..."
"There was a time when my father thought they might be useful," said Deirdre. "Then it looked like they wouldn't. Now it looks like they may."
Terry was tempted to say, "Useful for what?" But Davis' vague talk of unpleasant wrong guesses which led to even less pleasant ones had already been an admission that no convincing answer could be given him. Davis came over to him.
"This has me worried," he said in a frustrated tone of indecision. "We must be near the end of some process that I didn't suspect, and the conclusion of which I can't guess. I don't know what it is, and I don't know what it's for. I only know what it's tied in with."
Terry said absorbedly, "Two or three times I've picked up some new kinds of sounds. You might call them mooing noises. They're very faint, as if they were far away, and there are long intervals between them. I don't think they come from the surface."
Davis made an irresolute gesture. He seemed to hesitate over something he was inclined to accept. Deirdre protested before he could speak. "I don't think what you're thinking is right!" she said firmly. "Not a bit of it! Whatever happens will be connected with the fish. La Rubia has been around this sort of thing over and over again! We haven't been running the engine and we haven't been making any specific noises in the water to arouse curiosity! If anything were going to happen to us, it would have happened to La Rubia before now! It would be ridiculous to run away just because I'm on board!"
Terry, bent intently over the recorder, suddenly felt a cold chill run up and down his spine. His mind told him it was ridiculous to associate distant mooing sounds, underwater, with a completely unprecedented, frantic gathering of fish into one small area, and come up with the thought that something monstrous and plaintive was coming blindly to feed upon fellow creatures of the sea. There was nothing to justify the thought. It was out of all reason. But his spine crawled, just the same.
"The circle's only eight hundred yards across, now," said Davis, uneasily. "The fish can't crowd together any closer! But Doug went overboard with diving goggles, and he says there's a column of brightness as far down as he can make out."
Terry looked up.