"I could not say whether he was an American or an Englishman. We took him for the latter. But now I am coming to the real part of the story.
"In addition to the money which he deposited, he also left with us a small brass-bound box, in which he said there were valuable papers. He gave orders that it should be delivered to no one but himself in person, or until the expiration of ten years. The ten years will be up in a few days and this afternoon I bethought me of the box. But when I went into the vault in which it has been kept for so many years, the place upon an upper shelf, where it has always stood, was vacant. The box was gone!"
"Gone?" exclaimed all the boys in unison. "Do you mean stolen?"
"So it would appear."
"How could it have been done?" asked Adrian.
"I cannot say; but the strange thing about the whole matter is that in place of the box, there lay upon the shelf an envelope—yellow with age, upon which was written in ink that had scarcely faded the words: 'Montezuma's Mine.'"
"Well, what do you think of that?" queried Billie, looking at the others in amazement.
"I don't think," laughed Adrian. "It's up to you to do the thinking."
"Is there no clue whatever?" asked Donald.
"Not that could be really called a clue. The only suspicious thing that has happened to-day at all, was that a mountebank came into our bank——"