oming here, though, of
course, I am anxious to inspect the new aerial warship you have
constructed. So watch out for two things--your inventions, and, more
than all, your life!"

"Do you really think they would do me bodily harm?" Tom asked, a trifle
skeptical.

"I certainly do. These foreign spies are desperate. If they cannot
secure the use of these inventions to their own country, they are
determined not to let this country have the benefit of them."

"Well, I'll be careful," Tom promised. "I'm no more anxious than anyone
else to run my head into danger, and I certainly don't want any of my
shops or inventions destroyed. The fire in the red shed was as close as
I want anything to come."

"That's right!" agreed Ned. "And, if there's anything I can do, Tom,
don't hesitate to call on me."

"All right, old man. I won't forget. And now, perhaps, you would like
to see the Mars," he said to the lieutenant.

"I certainly would," was the ready answer. "But hadn't you better see
those men who are waiting to find out about positions here?"

"There's no hurry about them," Tom said. "We have applicants every day,
and it's earlier than the hour when I usually see them. They can wait.
Now I want your opinion on my new craft. But, you must remember that
it is not yet completed, and only recently did I begin to solve the
problem of mounting the guns. So be a little easy with your
criticisms."

Followed by Ned and Lieutenant Marbury, Tom led the way into the big
airship shed. There, Swaying about at its moorings, was the immense
aerial warship. To Ned's eyes it looked complete enough, but, when Tom
pointed out the various parts, and explained to the government officer
how it was going to work, Ned understood that considerable yet remained
to be done on it.

Tom showed his official guest how a new system of elevation and
depressing rudders had been adopted, how a new type of propeller was to
be used and indicated several other improvements. The lower, or cabin,
part of the aircraft could be entered by mounting a short ladder from
the ground, and Tom took Ned and Lieutenant Marbury through the
engine-room and other compartments of the Mars.

"It certainly is most complete," the officer observed. "And when you
get the guns mounted I shall be glad to make an official test. You
understand," he went on, to Tom, "that we are vitally interested in the
guns, since we now have many aircraft that can be used purely for
scouting p