"Let us examine every part of the boat," was the Professor's first suggestion. "We may find something more to give some clue."
The boys rushed down to the beach where the boat was moored, the Professor following.
"Show us the exact location of this strip."
"I had just taken off this cross seat, and as I did so this piece fell from the end."
"Let us put it back again and see how it fits into that place."
When it was replaced they noticed that a crack was left at each end of the seat, not exceeding an eighth of an inch.
"It is very plain that the piece you found was at this end, and if it was folded as this crease indicates, it could have been concealed there and thus escaped our observation." After some minutes' examination, he continued: "This piece must have been there for some time."
"Why do you think so?"
"You will notice that the end of the board has the marks of the folded paper, showing it must have been in its place of concealment for some time. Furthermore, the paper itself indicates that it has been there for some time, by the discoloration on its outer side."
"How long do you think it may have been there?"