They discussed this plan at some length, and agreed that it was the best thing to do.  Mr. Durban had a map of the country around the center of Africa, and he marked on it, as nearly as he could, the location of the pygmies’ country, while Mr. Anderson also had a chart, showing the location of the mission which had been wiped out of existence.  It was in the midst of a wild and desolate region.

“We’ll do the best we can,” declared Tom, “and I think we’ll succeed.  We ought to be there in about a week, if we have no bad luck.”

All that night the Black Hawk flew on over Africa, covering mile after mile, passing over jungle, forest, plains, rivers and lakes, and, doubtless, over many native villages, though they could not be seen.

Morning found the travelers above a great, grassy plain, dotted here and there with negro settlements which were separated by rivers, lakes or thin patches of forest.

“Well, we’ll speed up a bit,” decided Tom after breakfast, which was eaten to the weird accompaniment of hundreds of native warning-drums, beaten by the superstitious blacks.

Tom went to the engine room, and turned on more speed.  He was about to go back to 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!”