Tom Swift and His Giant Cannon

," went on Mr. Swift, as he resumed his chair, the young inventor in his airship having passed out of sight. "He's busy on some new invention now, I believe. I think I heard him say something about a new rifle."

"Cannon it was, Mr. Swift," said Mr. Damon. "Tom has an idea that he can make the biggest cannon in the world; but it's only an idea yet."

"Well, then I guess there's no hope of my interesting him in my opal mine," said the fortune-hunter, with rather a disappointed smile. "Nor you either, Mr. Swift."

"No, Alec, I'm afraid not. As I said, I'd rather give you outright three or four thousand dollars, if you wanted it, provided that you used it for your own personal needs, and promised not to sink it in some visionary search."

Mr. Peterson shook his head.

"I'm not actually in want," he said, "and I couldn't accept a gift of money, Mr. Swift. This is a straight business proposition."

"Not much straight business in hunting for a mine that's been lost for over a cen