“Freeman Hunt, that fellow who used to——”

But the others had shot out of the barn at top speed.

“I’ll give that fellow a lesson if I catch him prowling around here,” growled Merritt.

But, although they searched about the place thoroughly, they could find no trace of the intruder. When they got back to the shed, they found Paul putting up an old sack over the window through which the face had peered.

“I’m not going to take any chances with this machine,” the lad said earnestly, “and I want you fellows to promise not to tell any one about it.”

“All right,” they readily agreed.

“Isn’t it patented yet?” inquired Rob.

“No,” rejoined Paul. “I’ve put the matter in the hands of a lawyer in Washington, a friend of my dead father. I guess he’ll put it through. I want to sell it and pay off the mortgage on the house; but, in the meantime, I don’t want any one to know its details whom I can’t trust.”

“Well, the secret’s safe with us, Paul,” Rob assured him, as they parted for the night, “but don’t tell too many people about it. That’s a valuable invention, to my mind, and you want to guard it closely.”

“I will,” Paul promised, but he did not tell Rob that earlier in the week he had confided his great secret to Freeman Hunt. That worthy had heard something of a mysterious machine the lad was constructing, and took occasion to find out what it was. By flattering the unsuspecting boy, and telling him what marvelous things he had heard of him, Freeman soon put himself in possession of the details of the machine’s construction, and of the things Paul expected to accomplish.