Ned--that we are working together."

"He's sure doing a lot of Sherlock Holmes stunts," Jimmie declared.
"And I reckon he's next to his job, for he appears to have inspected
all the points of interest, from the field where the Nelson is to
the room where the plans are being made."

"Yes," Leroy said, his manner showing apprehension as well as anger,
"but how the Old Scratch did he get his knowledge, of what, we are
about to do? I thought no one in the West knew except us four. And
what's he trying to do, anyway? What difference does it make to him
if we do go to South America in an aeroplane?"

"I have a notion," Gates replied, "that he objects to your going in
an airship because you will make such swift time. Let me tell you
something more about this case. Then you will be able to understand
why efforts may be made to prevent your going to South America, in
an airship or in any other way."

"It's just the airship they've been after so far," Leroy
interrupted. "They haven't troubled us--and they'd better not!"

"I imagine," said the lieutenant, gravely, "that their activities
will broaden out as they get warmed up to their work. Understand?
What I mean is this: You boys are risking your lives in undertaking
this mission. You will be followed and spied upon from the minute
you leave San Francisco, and the chances will be all against you
when you reach your field of operations. Even the Government cannot
protect you in your undertaking, for the Government is not supposed
to know anything about this case."