And wait they did. In spite of what Captain Merceau had said, the boys did not relax their vigilance, but though, to their minds, the two men acted suspiciously, there was nothing definite that could be fastened on them.
Watchful guard was maintained night and day against an attack by submarines, and though there were several alarms, they turned out to be false. And in due season, the vessel arrived at "an English port," as the papers stated.
"Let's go and see if Captain Merceau wants us to give any evidence against those fellows," suggested Joe; and this seemed a good plan to follow.
"Ah, yes, my American friends!" the commander murmured, as the boys were shown into his cabin. "What can I do for you?"
"We thought we'd see if you wanted us in relation to the arrest of Secor and Labenstein," answered Blake.
"Ah, yes! The two men who signaled the submarine. I have had them under surveillance ever since you made your most startling disclosures. I sent a wireless to the war authorities here to come and place them under arrest as soon as the vessel docked. I have no doubt they are in custody now. I'll send and see."
He dispatched a messenger who, when he returned, held a rapid conversation with the captain in French. It was evident that something unusual had taken place.
The captain grew more excited, and finally, turning to the boys, said in English, which he spoke fluently:
"I regret to tell you there has been a mistake."
"A mistake!" cried Blake.