From the Ocean from teh Stars by Arthur C. Clarke

that he had a room of his own. And the staff, while grumbling mildly at the extra work he involved, were also annoyed because they could discover so little about him. Don had several times found himself, rather to his surprise, defending Franklin against the criticisms of his colleagues.
    "He's not a bad chap when you get to know him," he had said. "If he doesn't want to talk about his past, that's his affair. The fact that a lot of people way up in the administration must be backing him is good enough for me. Besides, when I've finished with him he'll be a better warden than half the people in this room."
    There were snorts of disbelief at this statement, and someone asked:
    "Have you tried any tricks on him yet?"
    "No, but I'm going to soon. I've thought up a nice one. Will let you know how he makes out."
    "Five to one he panics."
    "I'll take that. Start saving up your money."
    Franklin knew nothing of his financial responsibilities when he and Don left the garage on their second torpedo ride, nor had he reason to suspect the entertainment that had been planned for him. This time they headed south as soon as they had cleared the jetty, cruising about thirty feet below the surface. In a few minutes they had passed the narrow channel blasted through the reef so that small ships could get in to the Research Station, and they circled once round the observation chamber from which the scientists could watch the inhabitants of the sea bed in comfort. There was no one inside at the moment to look out at them through the thick plate-glass windows; quite unexpectedly, Franklin found himself wondering what the little shark fancier was doing today.
    "We'll head over to the Wistari Reef," said Don. "I want to give you some practice in navigation."
    Don's torpedo swung round to the west as he set a new course, out into the deeper water. Visibility was not good today—less than thirty feet—and it was difficult to keep him in sight. Presently he halted and began to orbit slowly as he gave Franklin his instructions.
    "I want you to hold course 250 for one minute at twenty knots, then 010 for the same time and speed. I'll meet you there. Got it?"
    Franklin repeated the instructions and they checked the synchronization of their watches. It was rather obvious what Don was doing; he had given his pupil two sides of an equilateral triangle to follow, and would doubtless proceed slowly along the third to make the appointment.
    Carefully setting his course, Franklin pressed down the throttle and felt the surge of power as the torpedo leaped forward into the blue haze. The steady rush of water against his partly exposed legs was almost the only sensation of speed; without the shield, he would have been swept away in a moment. From time to time he caught a glimpse of the sea bed—drab and featureless here in the channel between the great reefs— and once he overtook a school of surprised batfish which scattered in dismay at his approach.
    For the first time, Franklin suddenly realized, he was alone beneath the sea, totally surrounded by the element which would be his new do main. It supported and protected him—yet it would kill him in two or three minutes at the most if he made a mistake or if his equipment
    failed. That knowledge did not disturb him; it had little weight against the increasing confidence and sense of mastery he was acquiring day by day. He now knew and understood the challenge of the sea, and it was a challenge he wished to meet. With a lifting of the heart, he realized that he once more had a goal in life.
    The first minute was up, and he reduced speed to four knots with the reverse jet. He had now covered a third of a mile and it was time to start on the second leg of the triangle, to make his rendezvous with Don.
    The moment he swung the little joy stick to starboard, he knew that something was wrong. The torpedo was wallowing like a pig, completely out of control. He cut speed to zero, and with all dynamic forces gone the