r, not unlike the distant rumble of
thunder or the hum of a great steamer's whistle heard afar in the
fog.

"What's that?" cried Ned.

"Lions," said Mr. Durban briefly. "They have been attracted by the
smell of cooking."

At that moment, and instantly following a very loud roar, there was
an agonized scream of pain and terror. It sounded directly in back
of the airship.

"A lion!" cried Mr. Anderson. "One of the brutes has grabbed a
native!"

Tom Swift caught up his rifle, and darted off toward the dark
jungle.

CHAPTER XVI

SEEKING THE MISSIONARIES

"Here! Come back!" yelled Mr. Damon and Mr. Anderson, in the same
breath, while the old elephant hunter cried out: "Don't you know
you're risking your life, Tom to go off in the dark, to trail a
lion?"

"I can't stand it to let the native be carried off!" Tom shouted
back.

"But you can't see in the dark," objected Mr. Anderson. He had
probably forgotten the peculiar property of the electric rifle. Tom
kept on, and the others slowly followed.

The natives had at once ceased their merrymaking at the roaring of
the lions, and now all were gathered close about the campfires, on
which more wood had been piled, to drive away the fearsome brutes.

"There must be a lot of them," observed Mr. Durban, as menacing
growls and roars came from the jungle, along the edge of which Tom
and the others were walking just then. "There are so many of the
brutes that they are bold, and they must be hungry, too. They came
close to our fire, because it wasn't so bright as the other blazes,
and that native must have wandered off into the forest. Well, I
guess it's all up with him."

"He's screaming yet," observed Ned.

Indeed, above the rumbling roars of the lions, and the crackling of
the campfires, could be heard the moaning cries of the unfortunate
black.

"He's right close here!" suddenly called Tom. "He's skirting the
jungle. I think I can get him!"

"Don't take any risks!" called Mr. Durban, who had caught up his own
rifle, that was now in working order again.

Tom Swift was not in sight. He had now penetrated into the jungle--into
the black forest where stalked the savage lions, intent on
getting other prey. Mr. Durban and Mr. Anderson vainly tried to
pierce the darkness to see something at which to shoot. Ned Newton
had eagerly started to follow his chum, but could not discern where
Tom was. A nameless fear clutched at the lad's heart. Mr. Damon was
softl