Suddenly a thought flashed across the boy. A thought that sent him, with a swift, noiseless stride, to the rail. He peered overside. It had just occurred to him that Jarrold’s cabin was an outside one on the port side of the Tropic Queen, which presented that flank to the stranger.
As he gained the side and peered over, he gave vent to what was almost a shout of triumph. He had solved part of the riddle at any rate. After a pause in the signaling from the stranger, there had come from the side of the Tropic Queen a sudden flash of red light. It was reflected ruddily on the smooth water as it gleamed across the sea.
“So that’s it, eh, Mr. Jarrold!” cried Jack in a low undertone. “You’ve got some sort of a flash lantern rigged in your stateroom, connected with the electric light socket, likely, and you’re having a nice little talk with your friends over yonder.”
All at once he slapped his thigh as a thought struck him. He knew that a common switch controlled the lights in each separate corridor of the ship. Thus, the four cabins in the section that Jarrold occupied, while they each had their individual light switches, were also controlled by a switch in the main corridor.
This was so that, in case of accident, the electricians could work more conveniently.
“I don’t know what the skipper would say to this,” exclaimed Jack, “but here goes.”
He darted below and soon reached the point in the main port corridor from which the passage on which the four cabins in Jarrold’s section opened. He fumbled for the switch in the half darkness. First, though, he had looked to see that no other lights were shining in that section except the one he was sure was being used in Jarrold’s room.
Click! The switch was turned.
“Now we’ll see,” exclaimed Jack to himself.
He hastened back on deck. Through the night, off to the port the strange craft was signaling frantically. Jack chuckled.