open country, and free from observation. Then, in a remote
spot, where they could see for a long distance on every side, Wah Lee
stood still, and Bert ranged alongside.

"Well, Wah Lee," he asked, curiously, "what's the game?"

In answer, the Chinaman drew from his pocket a crumpled sheet of paper,
and handed it to Bert. He took it and smoothed it out. At first, it
failed to convey any impression. The drawing was a rough one, and seemed
to consist of a series of lines, punctured with dots. But gradually, as
Bert gazed, his training in mechanics told him that it was a plan of some
large structure. There were two rectangular outlines, that were
perfectly similar, like two leaves of a table. No, they were gates. And
then, like a flash, it came across him. They were the gates of the Gatun
Locks! There was the wavy line, to indicate the water level, and, down
below these, were the ominous dots. They seemed to be meant for holes,
but his knowledge of the locks told him that they had no place in its
structure. What did those holes mean?

A little shaken, he looked at Wah Lee for the key to the enigma.

"Where did you get this?" he asked.

"Found it," answered the Chinaman. "Man drop it. Man come to see my
bloss. My bloss kill clanal," Wah Lee repeated.

For a moment, Bert's head swam, and a thousand bells seemed to ring in
his ears. Then he steadied himself, and plied the Chinaman with eager
questions that sought to pluck the heart out of the mystery. Wah Lee's
knowledge of English was very limited, and it took a long time and
infinite patience to get from him what he knew. Gradually, he pieced the
bits together, until the whole thing became clear and coherent in his
mind.

By the merest accident, Wah Lee had heard enough to know that the
Japanese who employed him was engaged in a plot to destroy the Canal.
How or when it was to be done, he did not know. It was doubtful if he
could have grasped the details, even if he had heard them, so full they
were of technical matters that conveyed to him no meaning. But he knew
that the plot existed, and dimly understood that this would bring pain
and suffering to Bert. As far as he himself was concerned, a dozen
canals might be destroyed, without affecting him in the least. But he
held, the boys in strong affection for having saved his life, and he knew
that he could pay his debt, at least in part, by letting them know what
was brewing.

As regarded the pa