sturdy elephant hunter would not give up, and took his place again
after the wound had been bandaged.

From time to time as he worked his electric gun, which had been
charged to its utmost capacity, Tom glanced at the hut where the
missionaries were prisoners. There was no movement noticed about it,
and no sound came from it. Tom wondered what had happened inside--he
wondered what was happening as the battle progressed.

Fiercely the fight was kept up. Now the red imps would be driven
back, and again they would swarm about the airship, until it seemed
as if they must overwhelm it. Then the fire of the white adventurers
was redoubled. The electric rifle did great work, and Tom did not
have to stop and refill the magazine, as did the others.

Suddenly, above the noise of the conflict, Tom Swift heard an
ominous sound. It was a hissing in the air, and well he knew what it
was.

"The gas bag!" he cried. "They've punctured it! The vapor is
escaping. If they put too many holes in the bag it will be all up
with us!"

"What's to be done?" asked Mr. Durban.

"If we can't drive them back we must retreat ourselves!" declared
Tom desperately. "Our only hope is to keep the airship safe from
harm."

Once more came a rush of the savages. They had discovered that the