acted as private secretary to Mr. Langhorne, is missing and the
case has already attracted wide attention. Whether or not her
disappearance had anything to do with the robbery is not known.

"Naturally he would not report it to the police," commented
Kennedy; "that is, if it had anything to do with that Black Book,
as I am sure that it must have had."

"It was certainly a most peculiar affair if it did not," I
remarked. "There must be some way of finding that out. It's
strange about Betty Blackwell."

Kennedy was turning something over in his mind. "Of course," he
remarked, "we don't want to come out into the open just yet, but
it would be interesting to know what happened down there at
Langhorne's. Have you any objection to going down with me and
posing as a reporter from the Star?"

"None whatever," I returned.

We stopped at the laboratory on the campus of the University where
Craig still retained his professorship. Kennedy secured a rather
bulky piece of apparatus, which, as nearly as I can describe,
consisted of a steel frame, which could be attached by screws to
any wooden table. It contained a lower plate which could move
forward and back, two lateral uprights stiffened by curved braces,
and a cross piece of steel attached by strong bolts to the tops of
the posts. In the face of the machine was a dial with a pointer.

Kennedy quickly took the apparatus apart and made it up into two