Mr. Damon returned to the living-room, where he had first been carried.

"I cannot thank you enough for what you have done for me," he said. "I might have lain there for hours. Bless my very existence! I have had a very narrow escape. Hereafter when I see anyone on a motor-cycle I shall turn my head away. The memory will be too painful," and he touched the plaster that covered a cut on his head.

"Mr. Damon," said Tom quickly, "will you sell me that motor-cycle?"

"Bless my finger rings! Sell you that mass of junk?"

"It isn't all junk," went on the young inventor. "I can easily fix it; though, of course," he added prudently, "it will cost something. How much would you want for it?"

"Well," replied Mr. Damon, "I paid two hundred and fifty dollars last week. I have ridden a hundred miles on it. That is at the rate of two dollars and a half a mile--pretty expensive riding. But if you are in earnest I will let you have the machine for fifty dollars, and then I fear that I will be taking advantage of you."

"I'll give you fifty dollars," said Tom quickly, and Mr. Damon exclaimed:

"Bless my liver--that is, if I have one. Do you mean it?"

Tom nodded. "I'll fetch you the money right away," he said, starting for his room. He got the cash from a small safe he had arranged, which was fitted up with an ingenious burglar alarm, and was on his way downstairs when he heard his father call out:

"Here! What do you want? Go away from that shop! No one is allowed there!" and looking from an upper window, Tom saw his father running toward a stranger, who was just stepping inside the shop where Mr. Swift was constructing his turbine motor. Tom started as he saw that the stranger was the same black-mustached man whom he had noticed in the post-office, and, later, in the restaurant at Mansburg.