"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."