nging down into the
little chamber.

As he reached it, a door leading to the outer air flew open, and out
rushed a man, badly torn as to his clothes, and scratched and bleeding
as to his face. On he ran, across the space back of the barbette,
toward the lower tier of seats that had been erected for the spectators.

"It's von Brunderger's servant!" gasped Ned, recognizing the fellow.

"What did he do, Koku?" demanded the young inventor.

"Him sneak in here--have some of that stuff you call 'dope.' I sent up
powder, and I come back here to see him try to put some dope in
Master's ammunition."

"The scoundrel!" cried Tom. "They're trying to break me, even at the
last minute! Come on, Ned."

They raced outside to behold a curious sight. Straight toward von
Brunderger rushed the man as if in a frenzy of fear. He called out
something in German to his master, and the latter's face went first
red, then white. He was observed to look about quickly, as though in
alarm, and then, with a shout at his servant, the German officer rushed
from the stand, and the two disappeared in the direction of the
barracks.

"What does it mean?" cried Ned.

"Give it up," answered Tom, "except that Koku spoiled their trick,
whatever it was. It looks as if this was the end of it, and that the
mystery has been cleared up."

"Mr. Swift! Where's Mr. Swift?" shouted the wireless operator. "Where
are you?"

"Yes; what is it?" demanded Tom, so excited that he hardly knew what he
was doing.

"The longest shot on record!" cried the man. "Thirty-three miles, and
it struck, exploded, and blew the top off a mountain on an island out
there!" and he pointed across the sun-lit sea.

CHAPTER XXV

THE LONG-LOST MINE

There was a silence after the inspiring words of the operator, and then
it seemed that everyone began to talk at once. The record-breaking
shot, the effect of it and the struggle that had taken place in the
powder room, together with the flight of von Brunderger and his
servant, gave many subjects for excited conversation.

"I've got to get at the bottom of this!" cried Tom, making his way
through the press of officials to where the wireless operator stood.
"Just repeat that," requested Tom, and they all gave place for him,
waiting for the answer.

The operator read the message again.

"Thirty-three miles!" murmured Tom. "That is better than I dared to
hope. But what's that about blowing the top off an island?"

"That'