did stroll over to where, down in the front part of the stand, the odd student was screwing some hinges on the doors of a row of boxes, the seats in which sold for higher prices than the ordinary ones. Lenton was a strange lad. He was bright in his studies, and his taste ran to matters scientific. He was eager in the physics and chemistry classes, and had made a number of ingenious machines and pieces of apparatus to illustrate the forces of nature.
As Tom approached he heard the shrill scraping of a file, and at once what Phil had said about the key came into his mind.
"I wonder what Lenton is filing?" thought the end. Not wishing to seem to sneak up on him, yet desiring to solve the mystery, if there was one, Tom called:
"What's the matter? Don't those hinges fit, Lenton?"
"Some of them do, and others don't," was the reply. "Or, rather, the hinges are all right, but the hasps that hold the doors shut aren't true. I have to file some."
"Oh," said Tom, and then he noticed that the lad had rigged up a small, portable iron vise on the rail near which he was working. The vise held a piece of metal, and this the lad was industriously filing.
As Tom noticed the manner in which Lenton
