Frank laughed.
“Doubtless they think us a government boat or war vessel,” he said. “Their trade may be of an illicit kind.”
However this was, the lugger certainly got out of the way very rapidly. She was soon lost to view.
They were now well into the Yucatan Channel. Wilbur Wade was a very busy man.
He was hurriedly making his reckoning and drawing his lines for exploration. The Sea Diver sailed slowly westward the while.
At length she came to a stop. It was at this point that the quest was to begin.
If there was really such a thing in existence as the Sunken Isthmus this was certainly the locality to look for it.
“I have been thinking about that sunken Isle of Mona,” said Wade. “Why might it not have been a part of the isthmus?”
“Very likely,” agreed Frank. “We may be directly over it now.”
“Eh!” exclaimed Wade, with a start. “And if we should come across the treasure——”