k behind a tree,
and they never once suspected that anybody was near. One was a tall,
thin man, a German, I thought, while the other was dark and
short,---fact is, I took him for a Chinese, a Japanese or a Korean
from the color of his skin and his black bristling hair."

"That sounds interesting, anyway!" commented Bud. Then he added with
a little amused laugh, "P'raps they've heard in some mysterious way,
Hugh, how a celebrated young inventor named Bud Morgan means to try
out his latest wonderful stunt, and they hope to steal the concrete
result of his budding genius. But go on, Ralph. What did they do
that looked suspicious?"

"Oh! their every action struck me as queer," Ralph continued.
"You see they talked in a low voice, put their heads close together,
looked all around as if they were afraid some one might be watching
them, and then moved off, always turning to the right and to the left.
You know when valuable iron ore was discovered on our farm, for a
long time afterward strange men came prowling around there. It struck
me these fellows might be looking for something like that."

"Perhaps they're really civil engineers, meaning to run a line across
here in order to straighten the railroad and save time on through
trains," Hugh suggested, leaning back after finishing his meal.

"That might account for it," Ralph admitted, "though they acted
mighty strange to me. I never let out a peep till they'd disappeared
from sight; and even then I thought it best to change my line of
advance for fear that I might stumble on the precious pair again.
Really now, I'd give a cooky to know just who and what they are,
and why they've come away up here where only charcoal burners can
be met as a rule."

Bud had opened his mouth to make some remark, sighing to think how
he was utterly unable to eat another bite, when there was a sudden
vivid flash as of lightning without that startled all the scouts;
and immediately following came a tremendous roar similar to a clap
of nearby thunder!

CHAPTER III

THE MYSTERIOUS EXPLOSION

"Wow! that was a stunner all right!" exclaimed Bud. "Why, honest,
I could feel the ground shake under me when that thunder clap came!
And as I happened to be looking over there where the opening lies,
the flash nearly blinded me."

"Lightning and thunder in November is something you don't often meet,"
was the comment of Ralph, turning a perplexed face toward Hugh, as
though depending on