been so very far, Senorita."

Lucia made a little grimace.

"I'm nearly seventeen," she said.

"Botheration!" said Billie. "We are not here to discuss ages, but
to find out how this box came here. I have no doubt that Lucia
has seen many similar boxes in her time."

"Well," asked Donald, somewhat nettled, "what do you propose to
do?"

"In the first place, I want to search the house."

"That's a good idea," declared Adrian. "Donna Lucia, will you
lead the way?"

"Certainly. Right this way; but don't go into father's room. I
know there is no one in there. One of the servants has been with
him every minute of the time."

Headed by Lucia, the boys explored the house from top to bottom,
but not a sign of any one could they find. So far as they could
determine, the box must have come in of its own self.

"I'll tell you one thing we can and must do," said Billie, after
they had returned to the library. "We must keep a watch in this
room to-night. Whoever put the box here may return."

"Right!" from Don. "You do have occasional lucid intervals,
Billie."

Billie grinned, but made no reply.

"I think we may all stay here for a few hours," suggested Lucia.
"Father is so much better that I think we may have a little
music. I will play some accompaniments on the guitar and Josie
can sing."

"That will seem a good deal like being back in the States,"
declared Adrian. "With the Stars and Stripes flying over my head,
a brigade of American troops on guard and an American girl
singing, I can almost forget I am on Mexican soil."

"How about the accompanist?" queried Billie.

"Oh!" laughed Adrian, "we're quite willing to adopt her. Hey,
Donald?"

"Don't ask me, Ad. Ask Billie."

"I am sure we could do no better," was Billie's gallant reply.

Lucia's suggestion was carried out and for a couple of hours
there was a merry little party under Santiago's hospitable roof.
Even the mysterious box was forgotten and the young people were
giving themselves up to a jolly good time, when suddenly there
came a scream which caused every one to turn their eyes toward
the room in which the sick man was supposed to be lying.

But there in the doorway he stood, his long night robe reaching
nearly to the floor and his thin black hair standing almost on
end.

"Father!" cried Lucia, rushing toward him "What is it?"

He waved her off, but made no reply, while with his long bony
finger he pointed at the brass-bound box.

"Where di