Jack's quick mind took in the situation on the instant.
"But you are no German," he protested.
"No, I'm English. Name of Davis. But I am in the game for what it's worth, the same as you are."
"I see," said Frank. "And you have been sent after our information?"
"Yes; and I shall have to hurry. We may be interrupted at any moment."
"We haven't had time to jot down anything," said Jack, "but we'll tell you what we have learned."
He whispered for some moments and Davis nodded understandingly. At last the boy ceased his whispering.
"And that's all you know?" asked Davis.
"Absolutely all," replied Jack, and added to himself, "and a whole lot more than I know, for that matter."
"Then," said Davis, "you believe that if we can get to the mouth of the Thames we can learn the whole secret?"