For answer Tom waved his hand toward the thick jungle all about them.

“We haven’t room to get a running start of ten feet.” he said, “and without a start the airship can never rise as a mere aeroplane. The only way we can get up from the jungle is like a balloon, and without the gas—”

He paused significantly. The sound of the war drums became louder, and to it was added a weird singing chant.

“The natives!” cried Mr. Anderson. “They’re coming right this way! We must fight them off if they attack us!”

“Where’s the electric rifle?” asked Ned. “Get that out, Tom!”

“Wait!” suggested Mr. Durban. “This is serious! It looks as if they were going to attack us, and they have us at a disadvantage. Our only safety is in flight, but as Tom says we can’t go up until the gas machine is fixed, he will have to attend to that part of it while we keep off the black men. Tom, we can’t spare you to fight this time! You repair the ship as soon as you can, and we’ll guard her from the natives. And you’ve got to work lively!”

“I will!” cried the young inventor. “It’s luck we have a spare cylinder!”

Suddenly there was a louder shout in the jungle and it was followed by a riot of sound. War drums were beaten, tom-toms clashed and the natives howled.

“Here they are!” cried Mr. Anderson.

“Bless my suspenders!” shouted Mr. Damon. “Where is my gun?”