a
cluster of stars called the Compasses."

"But what has that to do with the locations of the three islands?"

"They are situated, with relation to each other, exactly the same as the
three stars are placed in the heavens."

"What was the object of the three crosses before the star?"

"The three represented thirty."

"Thirty what?"

"Leagues."

"And the arrow?"

"The direction from Spica."

"Why from Spica?"

"Because that star is the one which represents the island on which this
particular chart happens to be found."

"Do you mean that a similar chart will be found on each island?"

"No; on only two of them."

The boys were astounded at this information. John and the Professor
remained quiet while the boys thus questioned Clifford.

John interrupted to inquire why there were only two charts.

"The record is found on the third."

"So Wonder and Venture Islands are the only ones which have the
inscriptions on the skulls?" asked Harry.

Clifford sat up with such a sudden start that the boys were alarmed. He
leaned forward, and hurriedly asked the following questions: "You say,
'Inscriptions on the skulls?' How do you know? and why do you say that
they are on Wonder and Venture Islands?"

"Because we have two of them."

He dropped back on the pillow, and reflected for some time, and then
slowly said: "But there must be three. One of them is still with the
records."

"No; we have the one with the records."

A smile illuminated his features, the tension was relaxed, and he
dropped back, and pressed his hands over his forehead, as he muttered:
"I am so glad, so glad, so glad," and his voice died down, and he
remained quiet, as though in sleep.

The questioners sat there in silence, and watched him as he slept. The
Professor motioned them to withdraw, and they passed into the adjoining
room.

"It is clear to me now," remarked John. "The knowledge of the record was
known to others, and I was not aware that any one besides ourselves
really had figured out the secret," remarked John, as he turned to the
Professor.

"Well, I came pretty close to it," exclaimed Harry. "I told you that the
three X's meant thirty leagues."

"So you did," said John. "Prior to the finding of the skull I did not
know of the full inscription. Its significance did not come to me until
we reached Venture Island."

"I remember now! I told George that I saw the chart you had made."

John smiled. "It would have deceived y