our hearing for us. This one does Benes' hearing for him. It vibrates to sound in different patterns. See?"
Now Grant saw. It was almost like a shadow in the fluid; a huge, flat shadow whipping past them.
"It's a sound wave," said Michaels. "At least, in a manner of speaking. A wave of compression which we somehow make out with our miniaturized light."
"Does that mean someone is talking?" asked Cora.
"Oh, no, if someone were talking or making any real sound, this thing would heave like the granddaddy of all earthquakes. Even in absolute silence, though, the cochlea picks up sounds; the distant thud of the heartbeat, the rasp of blood working through the tiny veins and arteries of the ear and so on. Didn't you ever cup your ear with a shell and listen to the sound of the ocean? What you're listening to mainly is the magnified sound of your own ocean, the blood-stream."
Grant said, "Will this be dangerous?"
Michaels shrugged. "No worse than it is -If no-one talks."
Duval, back in the work-room and bent over the laser once more, said, "Why are we slowing? Owens!"
Owens said, "Something's wrong. The engine is choking off and I don't know why."
There was the slowly intensifying sensation of being in a down-dropping elevator as the Proteus settled lower in the duct.
They hit bottom with a slight jar and Duval put down his scalpel. "Now what?"
Owens said anxiously. "The engine is overheating and I had to stop it. I think ..."
"What?"
"It must be those reticular fibers. The damned seaweed. It must have blocked the intake vents. There's nothing else I can think of that would be causing this."
"Can you blow them out?" asked Grant, tensely.
Owens shook his head. "Not a chance. Those are intake vents. They suck inward."
"Well, then, there's only one thing to do," said Grant. "It has to be cleaned off from the outside and that means more skin-diving." With furrowed brow, he began to clamber into his diving outfit.
Cora was looking anxiously out the window.
She said, "There are antibodies out there."
"Not many," said Grant, briefly.
"But what if they attack?"
"Not likely," said Michaels, reassuringly. "They're not sensitized to the human shape. And as long as no damage is done to the tissues themselves, the antibodies probably will remain passive."
"See," said Grant, but Cora shook her head.
Duval, who had listened for a moment, bent down to look at the wire he was shaving, matching it against the original wire thoughtfully, and then turning it in his hands slowly to try to gauge the evenness of its cross-section.
Grant dropped out the ventral hatch of the ship, landing on the soft-rubber elasticity of the lower wall of the cochlear duct. He looked ruefully at the ship. It was not the clean, smooth metal it had been. It looked furry, shaggy.
He kicked off into the lymph, propelling himself toward the bow of the ship. Owens was quite correct. The intake valves were choked with the fibers.
Grant seized a double handful and pulled. They came loose with difficulty, many breaking off at the surface of the vent filters.
Michaels' voice reached him over his small receiver. "How is it?"
"Pretty rotten," said Grant.
"How long will it take you? We've got a 26 reading on the Time Recorder."
"It's going to take me quite a while." Grant yanked desperately, but the viscosity of the lymph slowed his movements and the tenacity of the fibers seemed to fight back.
Within the ship, Cora said, tensely. "Wouldn't it be better if some of us went out to help him?"
"Well, now," began Michaels, doubtfully.
"I'm going to." She seized her suit.
Michaels said, "All right. I will, too. Owens had better stay at the controls."
Duval said, "And I think I had better stay right here, too. I have this thing almost done."
"Of course, Dr. Duval," said Cora. She adjusted her swimming mask.
The task was scarcely eased by the fact that three of them were soon wiggling about the ship's bow; all three snatching desperately at the fibers, pulling them loose, letting them drift away in the slow current. The metal of the filters was beginning to show and Grant pushed some recalcitrant pieces into the vent.
"I hope this doesn't do any harm, but I can't get them out. Owens, what if some of these fibers get into the vents; inside, I mean."
Owens voice in his ear said, "Then they get carbonized in the motor and foul it. It will mean a nasty cleaning job when we're through."
"Once we get through, I don't care if you have to scrap