"Excuse me, Carnes; that will keep. Let me read these telegrams."
For half an hour silence reigned in the laboratory. Dr. Bird laid down the last message with a sigh.
"Carnes," he said, "I'm check-mated. I sent out a hundred ultra-sensitive short wave receivers yesterday. Four of them were located within fifty miles of Wilmington, North Carolina. One of these four was destroyed, but none of the others detected a sign of a wave during the attack. One of them was within a hundred feet of the edge of the hole. If he isn't using a ray of some sort, what on earth is he using?"
"It looked like a flash of red light when it came from the submarine."
"Yes, but it couldn't be light. Let me think."
The doctor sat for a few minutes with corrugated brows. Suddenly he sprang to his feet.
"I deserve to be beaten," he cried. "Why didn't I think of that possibility before?"
e hurried into his laboratory and brought out a small box with a glass front. From the top projected a spike topped with a ball. Through the glass, Carnes could see a thin sheet of metal hanging pendant from the spike.