hed for visible light. He found it, far down the
face of the reef.

The camera made it easy, and his mind was at rest because this time
nature had made it impossible for their bubbles to give them away to
surface watchers.

There were heavy swells on the surface. He knew it because of the
pressure surges on his ears. But otherwise there was no sign of the
storm. He grinned because he suddenly realized that he felt dry. On the
surface, with the rain beating at him, he had felt like a drowned
kitten.

Moving with the confidence gained in his first experience, he led the
way seaward, then went to the level of the light. Soon they were close
enough to see the frogmen working over something on a coral ledge on the
reef face. They hovered motionless, watching, and as one of the frogmen
moved they saw that it was the brass ball.

Rick started his camera. He had an advantage, because the frogmen were
concentrating on what they were doing, their backs to him. He moved in
cautiously, camera grinding, then backed away again when he thought he
had enough long shots.

One frogman moved away a few feet, and Rick's breathing stopped as the
man's belt light flashed toward him. Had the frogman been looking, he
could have seen the boys, but he was too interested in the second
frogman's actions.

The second frogman crouched over the brass object, hand moving.

Rick recoiled as a wail lanced through his head with painful impact. He
felt the rope tighten as Scotty involuntarily drew away.

It was not the octopus, then! It was the brass ball that wailed. But
why? For what possible reason?

The frogmen were apparently satisfied. One of them picked up the
powerful light they had been using and turned it off. Then, with only
belt lights, they started back up the reef.

Rick waited until the lights were no longer visible. He glanced at his
depth gauge and wrist watch. They were at eighty feet, and they had
plenty of air left. He swam to the brass ball, camera grinding.

He had never seen anything quite like it. The brass sphere was mounted
on a box about twelve inches square and six inches high. From the
sphere, two rounded projections thrust out. He identified a waterproof
switch on the box, and two small knobs mounted on calibrated plates.
These were obviously controls, but he had no idea what they controlled.

Steve would want a few close-ups. Rick worked his camera focus and took
shots from every angle. When he had enough, he