“Hello there! Who’s prowling around?”

His words, spoken quietly, had an effect that astonished him. Someone moved out of the shadows and for a second into the faint light which streamed in through a port hole. Instantly Terry recognized one of the men who had attacked the professor on the previous night.

The man ran to the door, jerked it open and darted along the narrow hallway that led to the companionway ladder. Terry swung his feet over the edge of his bunk.

“All hands to repel boarders!” he yelled, and without waiting to put on shoes or clothing, dashed out of the door after the fleeing man.

The others woke up instantly, to see Terry streaking down the hall. Terry ran rapidly up the ladder and saw the intruder slipping over the rail. The steamer was close into the shore, and without hesitation the man dropped over into the water and struck out for the shore, just as Terry gained the rail.

While he watched the man swimming for shore the others ran up, followed a moment later by the captain and the mate, a lean-jawed man with a hooked nose and wide mouth. To their excited inquiries Terry explained what had happened.

“No use trying to catch him with a boat,” decided the captain, seeing that the man was almost to the shore. “What did he look like?”

Terry described him, and the professor and the boys were astonished to find that it was one of the men who had attacked the professor on the previous night. The captain broke out in an exclamation.

“Sackett!” he cried.

“You know him?” asked the professor.