“I think they’re the ones you accused my father of stealing,” said Ned. “Hold on to them, Chief.”

“I will, young man,” was the cool answer.

Sullen and defiant, the prisoners were taken to jail. Then with Koku’s help Tom’s chest of secrets, with the papers, plans and patents intact, as the young inventor ascertained by a quick inspection, was taken to a storage vault in a local bank until it could be removed to Shopton.

“I must telephone dad the good news,” Tom said, when the robbers were safely disposed of. And when Tom got into communication with Mr. Swift the latter expressed his delight and also told of the mysterious message demanding a reward for the return of the box.

“I’ll pay myself the reward,” chuckled Tom.

Little remains to be told. As Ned suspected, the Liberty Bonds were those stolen from the Investment Company and it was proved that Fawn had taken them. Barsky and Blodgett were one and the same, as Tom suspected, and he was one of the prime movers in the plot to steal Tom’s secrets. He and others were sent to prison for long terms.

Mr. Blythe had acted in good faith, knowing nothing of the character of the men, who, for their own selfish ends, sought to have him act for them. They had plotted to get Tom’s papers, thinking that when they had possession of them they could force him to come to terms in the sale of his tidal engine and other devices.

Accordingly, after open measures had failed, trickery was resorted to. Blodgett, disguised as a Russian pattern-maker, sought and obtained employment. When he found he could not sneak away with the papers, because of the big chest, he attacked Tom, put him out of the way, and then so arranged matters that his confederates entered the place in the night, overpowered Koku, and left with the chest.

The men made good their escape, after tying Koku to the tree, and they had hoped to fly to the fastness of the western mountains, where they expected to make terms with Tom. But one of the gang, who was anxious to get cash in a hurry, persuaded them to land in the place near the trees and try to get money from the Swifts by offering to return the chest. It was this that caused the robbers to go into camp. They expected to open negotiations again over the telephone. However, Tom spoiled their plans.

“But I’m not going to take any more chances,” decided the young inventor several days later. “I’m going to have a special vault made to hold my chest of secrets.”