"No, it has to be countersigned by General Wailer. And, as he's
on the proving grounds now, you can't see him. He's getting ready
for the test of his new cannon."

"But that's just what we want to see!" cried Tom. "We want to
get in there purposely for that. Can't you send word to General
Wailer?"

"I can't leave my post," replied the sentry, shortly. "You'll
have to come another time, when the General isn't busy. You can't
get in unless he countersigns that permit."

"Then it may be too late to witness the test," objected the
young inventor. "Isn't there some way I can get word to him?"

"I don't think so," replied the sentry. "And I'll have to ask
you to leave this vicinity. No strangers are allowed on the
proving grounds without a proper pass."



CHAPTER VI

TESTING THE WALLER GUN


Tom looked at Ned in dismay. After all their work and planning,
to be thus thwarted, and by a mere technicality! As they stood
there, hardly knowing what to do, the sound of a tremendous