“Judging from the way they streaked it down the road, they won’t come back here unless they’re hauled. But what’s the idea of the treasure chest, Tom? Some new invention?”

“No, it’s just a plain, strong chest. I had it made to store away my secret inventions—the formulae, plans, blue prints and so on—until I can put them properly in a vault that I’m going to construct underground.” As Tom spoke he began putting into the chest a number of bundles of documents and drawings. “I had the chest made in Mansburg, and I was just wondering when they were going to deliver it when Koku brought it up,” he added.

“Those plans and blue prints must be worth a lot of money,” remarked Ned, with an appraising glance at them.

“Well, yes, you might say that,” admitted Tom, though not at all boastfully. “The tidal engine alone, when I get it perfected, ought to bring in a pretty penny—that is, if dad and I decided to sell it.”

“When you perfect it!” exclaimed Ned. “Why, it works like a charm now!”

“Yes, I know the model does,” admitted Tom. “But that doesn’t say it’s commercially practical yet.”

“To judge by some of the offers you got for even a small interest in it, I’d say it was a humdinger!” exclaimed Ned. “But then your name goes a long way, Tom. Once let it be known that your company has something new on the market, and you’re overwhelmed with offers. Take that gyroscope air flier your father helped work out——”

“Not so loud, Ned!” cautioned the young inventor. “I’m not ready to let the latest news of that get out yet. As you know, with the new stabilizer, it works on quite a different principle.”

“Right! But there’s no one around here now to catch your secrets, Tom.”

“You never know when some one is around,” was the cautious observation as the young inventor continued to pack blue prints into the chest. “It’s best to be on the safe side. We didn’t think any one was listening when you and I discussed plans for the new turbine, and yet we nearly got dished out of that.”