ghtly wounded the
bank clerk on the arm. The wound was at once treated with
antiseptics, after the window had been barricaded, and Ned declared
that he was ready to renew the fight. Tom, too, got an arrow scratch
on the neck, and one of the barbs entered Mr. Durban's leg, but the
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
gas bag was vulnerable, and were directing their arrows against
that. It was punctured in several more places. The gas was rapidly
escaping.

"We've got to retreat!" yelled Tom. He hurried to the engine-room,
and turned on the power. The great propellers revolved, and sent the
Black Hawk scudding across the level plain. With yells of surprise
the red dwarfs scattered and made way for it.

Up into the air it mounted on the broad wings. For the time being
our friends has been driven back, and the missionaries whom they had
come to rescue were still in the hands of the savages.

CHAPTER XXII

A NIGHT ATTACK

"Well, what's to be done?"

Tom Swift asked that question.

"Bless my percussion cap! They certainly are the very worst imps for
fighting that I ever heard of," commented Mr. Damon helplessly.

"Is the gas bag much punctured?" asked Ned Newton.

"Wait a minute," re