On the starboard side, likewise against the roof, was another engine, with disks at each end as large as dinner plates.
"H'm," mused Matt, trying to rub the ache out of his head so his brain would be clearer, "those disks are diaphragms, and must be connected, in some way, with the water pressure. I have it!" and a triumphant look crossed his face, "this is the diving engine, and that wheel"—he touched the wheel as he spoke—"controls it."
At one side was a cubic steel box.
"Air compressor," said Matt, touching the box.
On the floor, just where Matt had dropped into the well, were two levers. Matt lifted one of them. Instantly there came a gurgle and splash of water, directly under Carl and Dick.
"Avast, matey!" cried Dick. "I wouldn't fool with those things until you know more about them."
Muffled cries came from the Japs outside.
"They hear what's going on," laughed Matt, "and they don't like it. We're filling the submerging tanks, Dick," he explained.
"Then why don't we sink?"
"It takes the engine to help us sink—the diving engine and the motor."