“No, not yet,” decided Mr. Newton. “Ned may be all right and he’d hate any police notoriety. We’ll wait a few days.”

The few days that followed were anxious ones, not only for Ned’s parents, but also for Tom Swift. He had a double worry, divided between the disappearance of his trusted chum and manager and concern over the wreck of his new apparatus. The latter worry was more easily disposed of, however, though it meant hard work and delay.

Tom set some of his most trusted men at the labor of reconstructing the new apparatus, but in such a way that the secret could not be come at. Only certain unimportant parts were given out, and Tom and his father would make the more vital sections.

Since Tom already had on the market a telephoto machine and had also made several varieties of moving picture projectors, it was not a hard matter to let it casually be known that the new apparatus was an attempt to improve either or both of the old inventions. Thus was gossip stilled about the big Swift plant.

Tom, however, did not know what to think about Greenbaum. The day after the explosion the man was lamenting loudly that some of his own experimental apparatus, which he was working on for the Swift firm, had been destroyed in the fire and blast.

“And,” said Tom, telling his father about it, “since I have promised him a large bonus if he works out that magnetic gear shift, it doesn’t seem reasonable that he would set a bomb that might destroy the results of his own hard work.”

“No, Tom, it doesn’t.”

“And yet I can’t help suspecting him,” mused the young inventor. “He is as friendly as ever, and seems anxious to help me. But there is something furtive in his manner and in his looks.”

“Did Clark find out anything?”

“Only that Greenbaum went straight to his boarding place from here and did not go out again that night. He was at home when the explosion took place.”