“Of course,” replied Marquette. “The torpedoes are under electrical control. Then they came back.
“The little lights were set to twinkle so that they could be observed from the tower. Then, when they were near by, they shone, for they are coated with a luminous paint, so we can observe their approach.”
“But what came out of the lake?”
“I was responsible for that,” said Marquette. “The professor believes that he can invent a torpedo which may be shot from a submarine, yet which will take to flight when it reaches the surface of the water.
“There is a torpedo tube beneath the house — in a room deep in the basement. I was there. When I received his signal, I shot the torpedo through an under-water cave, out into the lake.
“It rose, but failed to soar. The professor was watching from the tower.”
THE eerie events of the preceding night were now clear. But Marquette had further explanations.
“I shall start at the beginning,” he said. “Much has happened here. Originally, Professor Whitburn believed that he could revolutionize modern warfare by the invention of an aerial torpedo. He interested a man named Jonathan Graham.”
“Graham is dead,” said Harry.
“What? How?”