o the pilot house, to set the automatic steering
apparatus to coincide with the course mapped out, when there was a
crash of metal, an ominous snapping and buzzing sound, followed by a
sudden silence.

"What's that?" cried Ned, who was in the motor compartment with his
chum.

"Something's gone wrong!" exclaimed the young inventor, as he sprang
back toward the engine. The propellers had ceased revolving, and as
there was no gas in the bag at that time, it having been decided to
save the vapor for future needs, the Black Hawk began falling toward
the earth.

"We're going down!" yelled Ned.

"Yes, the main motor has broken!" exclaimed Tom. "We'll have to
descend to repair it."

"Say!" yelled Mr. Damon, rushing in, "we're right over a big African
village! Are we going to fall among the natives?"

"It looks that way," admitted Tom grimly, as he hastened to the
pilot house to shift the wings so that the craft could glide easily
to the ground.

"Bless my shoe blacking!" cried the eccentric man as he heard the
beating of drums, and the shouts of the savages.

A little later the airship had settled into the midst of a crowd of
Africans, who swarmed all about the craft.

CHAPTER XIII

ON AN ELEPHANT TRAIL

"Get ready with your guns, everybody!" cried the old elephant
hunter, as he prepared to leave the cabin of the Black Hawk. "Tom
Swift, don't forget your electric rifle. There'll be trouble soon!"

"Bless my cartridge belt!" gasped Mr. Damon. "Why? What will happen?"

"The natives," answered Mr. Durban. "They'll attack us sure as fate!
See, already they're getting out their bows and arrows, and
blowguns! They'll pierce the gas bag in a hundred places!"

"If they do, it will be a bad thing for us," muttered Tom. "We can't
have that happen."

He followed the old elephant hunter outside, and Mr. Anderson, Ned
Newton and Mr. Damon trailed after, each one with a gun, while Tom
had his electric weapon. The airship rested on its wheels on some
level ground, just in front of a large hut, surrounded by a number
of smaller ones. All about were the natives, tall, gaunt black men,
hideous in their savagery, wearing only the loin cloth, and with
their kinky hair stuck full of sticks, bones and other odd objects
they presented a curious sight.

Some of them were dancing about, brandishing their weapons--clubs
spears, bows, and arrows, or the long, slender blowguns, consisting
merely of a hollow reed. Women and