"I think that you will soon be free to go back to the army," said the Chief. "Your work is about done. This thing is coming to a head fast now. But of course I shall need your boys to listen in for a time, so that we can know what the Germans are sending. But there will probably be no more real work for you. We certainly are grateful for the help you gave us, though. We have been terribly crowded these last few weeks."
In his pride at the work his boys had done, Captain Hardy momentarily forgot the errand that had brought him to the Chief's office. He stood before the head of the secret service, smiling happily. Again he began to think of that long chain of secret wireless stations, so sinister and so menacing, with voice crying treachery to voice through the air, carrying word that at any time might cause the murder of thousands of our brave soldiers. Mentally he journeyed along the line of those stations—from New York to Buffalo, to Detroit, to Milwaukee, to Omaha, to Santa Fé, to Socorro, to Mexico. With quick imagination he pictured the scores of little secret stations needed to carry those treacherous messages across so vast a span of earth. Some he saw skilfully hidden in forests, as the wireless had been concealed at the Elk City reservoir. Some he pictured in abandoned farmhouses. Others he saw in barns, in the stacks of ruined factories. And some he imagined as flinging their voices abroad amid the burning plains of the arid border-lands. But he could not picture to himself the invisible messenger that took the word across the boundary. He could not fathom the mystery, he could not picture to himself the missing link in the chain. As was always the case with him, his mind began at once to grapple with its problem—in this instance the riddle of the missing link. He actually forgot where he was.
"I wonder," he said, though he was really talking to himself, "what was done with that smuggler."
"We clapped him into jail to await trial for smuggling," said the Chief.
Captain Hardy came to himself with a start, and smiled. "You say they got nothing incriminating on him," he remarked. "Did your men find anything at all?"
"Only the money he had gotten for his tobacco."
Mechanically Captain Hardy had thrust his hand into his pocket. As the Chief answered the question, Captain Hardy's fingers came in contact with a silver dollar and a disc of celluloid. Of a sudden an eager light flashed into his eyes. "What kind of money did that Mexican have?" he demanded.
"Some silver," said the Chief indifferently.
"Of what denominations?"
"Dollars. He had three of them."