e patio.

"This is my house," said Don Esteban. "Be pleased to consider it
your own. Now, if you will follow me to the library, I will
explain the mission I wish you to undertake."

The boys followed without a word, but as they passed up the
stairs Billie muttered under his breath:

"Did you notice, boys, that this house backs right up against
Santiago's?"

CHAPTER XXIV.

DON ESTEBAN'S STRANGE LOSS.

"Before I explain to you the mission I wish you to undertake,"
said Don Esteban, "I must narrate briefly a story that has been
handed down from the days of Montezuma. It is to the effect that
when the Spanish conqueror, Cortez, was about to capture the City
of Mexico, most of the treasure of the Aztecs was sunk in the
lake, which at that time covered a portion of the Mexican
plateau.

"A part of this treasure is said to have been recovered, but the
mine from which the gold of Montezuma was taken has never been
discovered, although search has been made for upward of five
hundred years. Some have supposed that the mine was adjacent to
the City of Mexico and that it was flooded at the time the
treasure was sunk in the lake. Others have thought it was located
in the state of Michoacan, while still others have believed it
located in the vicinity of Mt. Orizaba.

"My reason for telling you this is that some years ago a strange
appearing man came to our bank and made a large deposit of money,
all in gold. He did not deposit it all at once, but brought it in
a few thousand dollars at a time until it amounted to more than a
million dollars. Then he disappeared and we have never seen him
since."

"And has he never called for any of the money?" asked Billie.

"Not in person, although he has drawn upon it at frequent
intervals. The name under which it was deposited is James Moon."

"An American?" asked Donald.

"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 st