“I thought so,” he said exultingly a moment 120 later. “I can see the dorsal fin of a shark out there.”

Disbelief vanished before his confident tone, and all looked eagerly in the direction he indicated.

“Perhaps it’s only a floating bit of wood,” said Teddy doubtfully, after a long gaze through the glasses.

“Let Lester look,” suggested Bill. “He knows a shark when he sees one.”

Lester relinquished the tiller to Bill and took a long, steady look through the binoculars.

“Bill is right,” he announced at last. “It’s a shark and a big one too. I guess we’re going to have some sport, after all.”

“But how are we going to get a trial at him?” cried Teddy. “He seems to be going in the opposite direction.”

“I guess he won’t go far,” replied Lester with easy confidence. “This is probably his feeding ground, and he’ll keep going round and round in lazy circles. We’ll get a little nearer to him before we do anything else.”

He retook the tiller and changed the Ariel’s course toward the spot where they had seen the shark.

“Lower the sail, now,” he commanded, when they had gone half a mile. “Just keep up enough to give us steerage way. A shark thinks a boat’s disabled when it isn’t moving much, and his instinct 121 teaches him that the occupants are probably in trouble and his chance of finally getting them will be better.”