midnight visitors were engaged in a hand-to-hand tussle with the
giant there came a sharp, throbbing roar of the airship motor in
motion. The propellers were being whirled rapidly about.

"Koku! Koku!" cried Tom, for he was still some distance off.
"Never mind them! Don't let the airship be taken!"

But Koku could only grunt. Big and strong as he was, half a dozen
men attacking him at once hampered him. He threw them from him,
one after another, and was gradually making his way toward the now
slowly-moving airship. But would he be in time?

Tom and Ned could not hope to reach the machine before Koku,
though they were running at top speed.

"Koku! Koku!" yelled Tom. "Don't let them get away!"

But Koku could only grunt--harder this time--for he fell heavily,
being tripped by a stick thrust between his legs. He lay for a
moment stunned.

"They're going to get away!" panted Tom, making an effort to
increase his speed.

"That's what!" agreed Ned.

Even as they spoke the roar of the airship motor increased.
Several of the dark forms which had been engaged in the struggle
with Koku were seen to pick themselves up, and run toward the
airship, that was now in motion, moving on the bicycle wheels over