"What's that?" he demanded.
"Oh, just a little idea I'm working on," said Jack, "a new invention. If I can perfect it, it may be valuable."
"Yes, but what is it? What's it for?" persisted Thurman.
Jack explained what he hoped to accomplish with the instrument, and an instant later was sorry he had done so, for he noticed an expression of cupidity creep into Thurman's eyes. The youth persisted in asking a host of questions, and Jack, having started to explain, could not very well refuse to answer. Besides, inventors are notoriously garrulous about their brain children, and Jack, even though he did not like Thurman, soon found himself talking away at a great rate.
"Huh, I don't think the idea's worth a cent," sniffed Thurman contemptuously, when Jack had finished.
"I guess that's where you and I differ," said Jack, controlling his temper with some difficulty, for the sneer in Thurman's voice had been marked. "I'm going to make it a success, and then we shall see."
He left the wireless room, and the instant he was gone Thurman, with a crafty look on his flabby face, eagerly began examining the detector. As he was doing so Jack, who had forgotten his cap, suddenly reëntered the wireless room. Thurman had been so intent on his scrutiny of the detector that he did not hear him.
"You appear to be taking great interest in that useless invention," said Jack in a quiet voice.
Thurman started and spun round. His face turned red and he had an almost guilty look.
"I didn't think you were coming creeping back like that," he exclaimed, "a fellow would almost think you were spying on him."