de 129 west.
Now, when they were picked up they had been driving for some thirty-six
hours before a southwest wind at not less than fifteen knots an hour.
This would make about five hundred and forty miles they had come from
the island, which must, therefore, lie somewhere between five or six
hundred miles to the southwest."

"I should think that would be the spot where he would look for it," said
Juarez.

"That is what he did, and so have I," was the reply, "but we were,
neither of us, able to locate it."

"Do you think it really exists?" asked Jim.

"I am quite certain of it," answered the professor. "At any rate, I am
going to make another attempt, and I want you to go along with me."

"What do you want with us?" questioned Jim.

"Well," replied the professor, slowly, "I need some efficient help, and
I have had my eye on you boys for some time. I had heard of you, that
you were thoroughly trustworthy and could be depended upon in any
emergency, and I decided that you were just the kind of companions I
wanted. But I may as well tell you right at the start that this is not
going to be a picnic party; we are going to have our work cut out for
us, and plenty of it, so if you go along you are likely to see some
pretty exciting times before we get through."

"That don't scare us any," put in Jo.

"I didn't think it would," the professor went on, "and if it turns out
as I believe it will, we shall all have all the money we need for the
rest of our lives."

"But why should you take us in?" persisted Jim.

"Why, if we should succeed in finding the treasure," the professor
explained, "it would be a great temptation to those who learned of it to
use any means, fair or foul, to get possession of it. That is one of the
reasons I want you. I feel that I can depend upon you through and
through."

"I think you can," responded Jim quietly, but not the less emphatically.
"What we say we are ready to stand by."

"I am quite sure of it. Now, the proposition I have to make is this: I
will finance the expedition, taking all the risk. Now wait"--to Jim, who
was about to interrupt. "If we succeed I will take one-half of what we
get. Out of my half I will provide for Brook's family. The other half I
will divide, one quarter for you and one quarter to the crew. How does
that strike you?"

"That's fair enough," agreed the boys.

"Should we fail, I will pay you for your time."

"Oh, we'll take our chances on that," broke in