then."

"Good!" exclaimed Tom. "I hope we can all bring back some of the
images."

"Yes, I know who you'll bring one for," said Ned with a laugh, and
he took care to get beyond the reach of Tom's fist. "Her first name
is Mary," he added.

"You get out!" laughed Tom, blushing at the same time.

"Ah! What a thing it is to be young!" exclaimed Mr. Damon with a
mock sigh. The boys laughed, for the old man, though well along in
years, was a boy at heart.

They talked at some length, speculating when they might hear from
Mr. Illingway, and discussing the sort of an outfit that would be
best to take with them.

Then, as the afternoon was drawing to a close, Tom and Ned went back
in the aeroplane, hearing the news about the Fogers as I have
previously mentioned.

"Well, I'll have to wait until I do see Andy to take it out of his
hide," remarked Tom grimly. "I'm glad he's out of the way, though.
There won't be any more danger of his overhearing our plans, and I
can work in peace on the dirigible balloon."

Though Tom had many air crafts, the one he thought best suited to
take with them on their search for the city of gold would have to be
constructed from parts of several machines, and it would take some
time.

Tom began work on it the next day, his father helping him, as did
Mr. Damon and Ned occasionally. Several weeks were spent in this
way, meanwhile the mails being anxiously watched for news from
Africa.

"Here you are, Tom!" called the postman one morning, as he walked
out to the shop where the young inventor was busy over the balloon.
"Here's another letter from that Buggy-wuggy place."

"Oh, you mean Gumba Twamba, in Africa!" laughed the lad. "Good!
That's what I've been waiting for. Now to see what the missionary
says."

"I hope you're not going to go as a missionary to Africa, Tom," said
the postman.

"No danger. This is just a letter from a friend there. He sent me
some facts so I can go off on another expedition."

"Oh, you're always going off on wild adventures," commented Uncle
Sam's messenger with a shake of his head as he hurried away, while
Tom tore open the letter from Africa and eagerly read it.

CHAPTER VI

"BEWARE THE HEAD-HUNTERS!"

"That's what I want!" exclaimed the young inventor, as he finished
the perusal of the missionary's missive.

"What is it?" asked Mr. Swift, entering the shop at that moment.

"News from Africa, dad. Mr. Illingway went to a lot of trouble to
g