He insisted, however, that he knew nothing of the headquarters of the gang or of their leader whom Henderson and his associates believed was a master criminal, an unscrupulous, fiendish character who, during the war, had undertaken to destroy the Leviathan, Brooklyn Bridge, the Navy Yard and many buildings as well as thousands of people in America and England, but who, failing in this, dared not return to Germany. The government officials felt confident that this same master mind was responsible for the wave of crime, the flood of Bolshevist literature and the threatening letters which had baffled them.

Mr. Pauling and Mr. Henderson were also most anxious to secure a statement from the other man, who was still unconscious in the hospital, and when at last he was able to speak Mr. Pauling hurried to his side. The dying man, thinking that his comrades had betrayed him, related an astounding story, admitted the existence of the master criminal and was on the point of revealing his headquarters when he died.

At almost the same time word was received that the submarine had been picked up, drifting at sea, by a destroyer despatched to find her, but that she was absolutely deserted. When at last she was towed into New York and was examined by Mr. Pauling, Rawlins and the boys she was found stripped of everything which would have thrown light upon the mystery. Questioning the crew of the destroyer, Rawlins discovered that a fishing schooner had been sighted near the drifting submarine and from the description he recognized it as a Bahaman vessel and jumped to the conclusion that the crew of the submarine had transhipped to it.

Believing that he could locate the headquarters of the plotters, Rawlins suggested that he and the boys should go to the West Indies and, after some objections had been overcome, this plan had been agreed to by Tom’s father. Thus it came about that the two boys were now upon a steamer’s deck as she churned her way through the intensely blue sea towards the palm-fringed islands beyond her bows.

“I wonder when Rawlins will get here with that sub,” remarked Mr. Henderson.

“Not for several days yet, I imagine,” replied Mr. Pauling. “There was a lot of work to be done upon her and she cannot make much over fifteen knots on a long cruise. I’m personally more anxious to hear from the destroyers that are chasing the schooner. I wonder if Rawlins was right in his surmise regarding her.”

“We should hear from them soon after we reach Nassau,” declared the other. “We left three days after the destroyers and that schooner certainly could not beat the destroyers to the islands or evade them. I don’t think there’s the least question about their overhauling her.”

“Say, won’t it be great if they do catch her,” exclaimed Tom, “and find the crew of the submarine aboard?”

“Yes, but it’s very evident they have not even sighted her as yet,” replied his father. “If they had we would have received a radio.”

“Perhaps they’re out of range of communication,” suggested Mr. Henderson.