“We weren’t ready for him,” said Joe mournfully.
“I’ll bet he thinks twice before he comes here again,” declared Chet.
“I don’t think we’ve seen the last of him,” Frank remarked. “There is something mighty important about that notebook, and I’m sure he is not the man to give up as easily as all that.”
Chet shook his head.
“He’ll just wait until we leave the island for good.”
“I don’t think so. He knows that we’re apt to stumble on the secret of that cipher at any time. I’m going to tackle that message again. It can’t be so very difficult.”
Frank immediately sat down at the desk, the cipher message before him, and began figuring on a pad of notepaper, while the other boys set about restoring the damage their visitor had created.
First of all, he set down all the letters of the alphabet in order, and studied them intently, with reference to the cipher.
“If I were writing a cipher,” he mused. “How would I go about it? Perhaps this thing is really a lot simpler than it looks.”
The easiest thing to do, he thought, would be merely to reverse the alphabet. Instead of the letter “a” he would use the letter “z.” Instead of the letter “b” he would use “y,” and so on.