start off," proposed Tom, "I
don't think it would be wise to remain on the ground so near the
jungle."

"No' it's safer in the air," agreed Mr. Durban. The meal was much
enjoyed, especially the fresh meat, and, after it was over, Tom took
his place in the pilot house to start the machinery, and send the
airship aloft.

The motor hummed and throbbed, and the gas hissed into the bag, for
the ground was not level enough to permit of a running start by
means of the planes. Lights gleamed from the Black Hawk and the big
search-lantern in front cast a dazzling finger of light into the
black forest.

"Well, what are you waiting for?" called Ned, who heard the
machinery in motion, but who could not feel the craft rising. "Why
don't you go up, Tom?"

"I'm trying to," answered the young inventor. "Something seems to be
the matter." He pulled the speed lever over a few more notches, and
increased the power of the gas machine. Still the Black Hawk did not
rise.

"Bless my handkerchief box!" cried Mr. Damon, "what's the matter?"

"I don't know," answered Tom. "We seem to be held fast."

He further increased the speed of the propellers, and the gas
machine was set to make vapor at its fullest capacity, and force it
into the bag. Still the craft was held to the earth.

"Maybe the gas has no effect in this climate," called Ned.

"It can't be that," replied Tom. "The gas will operate anywhere. It
worked all right today."

Suddenly she airship moved up a little way, and then seemed to be
pulled down again, hitting the ground with a bump.

"Something is holding us!" cried Tom. "We're anchored to earth! I
must see what it is!" and, catching up his electric rifle, he dashed
out of the cabin.

CHAPTER XII

AMONG THE NATIVES

For a moment after Tom's departure the others stared blankly at one
another. They could hear the throbbing and hum of the machinery, and
feel the thrill of the anchored airship. But they could not
understand what the trouble was.

"We must help Tom!" cried Ned Newton at length as he caught up his
rifle. "Maybe we are in the midst of a herd of elephants, and they
have hold of the ship in their trunks."

"It couldn't be!" declared Mr. Durban, yet they soon discovered that
Ned's guess was nearer the truth then any of them had suspected at
the time.

"We must help him, true enough!" declared Mr. Anderson, and he and
the others followed Ned out on deck.

"Where are you Tom?" called his chum.