Jack gave an exclamation of astonishment.
"What do you mean?" he asked.
"I don't know exactly," replied the boy. "Yesterday afternoon, while I was in the house alone, three strange men appeared at the door. They wore the costume of an ordinary seafaring man, but when they asked me for food they had a strange manner of speech. They weren't Americans, I'm sure of that."
"And you think they were from a submarine, eh?" asked Jack.
"I'm sure of it, Captain. There were no other ships near, and they could not have come overland, for it is a long ways to the nearest village and they had neither horses nor automobile."
"And what did you say to them?" asked Frank.
"I gave them what food there was in the house, but they said it wasn't enough. About this time my father came in unexpectedly. The strangers drew revolvers and covered him. They told him they would be back to-night and that they required him to have a certain amount of food on hand. They threatened to kill him if he gave the alarm—and they threatened to kill me too."
"By George!" exclaimed Frank. "It looks as though we had come to the right spot, Jack."
"It certainly does," agreed Jack. "Now tell us the rest of your tale, son."
"That's about all," said the boy. "They devoured what food I gave them and then disappeared."