“Take out all the braces that haven’t been moved and have a look,” suggested Mr. Sharp.  Tom only had to remove two, those farthest back, for all the others had, at one time or another, been changed or taken away by the thief.

One of the blocks did not seem to have anything unusual about it, but at the sight of the other Tom could not repress a cry.  It was the one that seemed to have had a hole bored in it and then plugged up again.  He remembered his father noticing it on the occasion of overhauling the boat.

“The sparkler’s in there,” said the tramp as he saw the brace.  “Boreck was after it several times, but he never pulled out the right one.”

With his knife Tom dug out the putty that covered the round hole in the block.  No sooner had he done so than there rolled out into his hand a white object.  It was something done up in tissue paper, and as he removed the wrapper, there was a flash in the sunlight and a large, beautiful diamond was revealed.  The mystery had been solved.

CHAPTER XXV

WINNING A RACE

“Where did this diamond come from?” demanded Mr. Sharp of the quartette of criminals.

“That’s for us to know and you to find out,” sneered Happy Harry.  “I don’t care as long as that trimmer Boreck didn’t get it.  He tried to do us out of our share.”

“Well, I guess the police will make you tell,” went on the balloonist.  “Go for the constable, Tom.”

Leaving his friend to guard the ugly men, who for a time at least were beyond the possibility of doing harm, Tom hurried off through the woods to the nearest village.  There he found an officer and the gang was soon lodged in jail.  The diamond was turned over to the authorities, who said they would soon locate the owner.

Nor were they long in doing it, for it appeared the gem was part of a large jewel robbery that had taken place some time before in a distant city.  The Happy Harry gang, as the men came to be called, were implicated in it, though they got only a small share of the plunder.  Search was made for Tod Boreck and he was captured about a week after his companions.  Seeing that their game was up, the men made a partial confession, telling where Mr. Swift’s goods had been secreted, and the inventor’s valuable tools, papers and machinery were recovered, no damage having been done to them.

It developed that after the diamond theft, and when the gang still had possession of Mr. Hastings’ boat, Boreck, sometimes called Murdock by his cronies, unknown to them, had secreted the jewel in one of the braces under the gasoline tank.  He expected to get it out secretly, but the capture of the gang and the sale of the boat prevented this.  Then he tried to buy the craft to take out the diamond, but Tom overbid him.  It was Boreck who found Andy’s bunch of keys and used one to open the compartment lock when Tom surprised him.  The