k that I nailed my watch up in that
last box."

"Nailed up your watch!" cried Mr. Preston, who, after a trip to New
York to make arrangements for passages on a steamer, had come back
to help Tom pack up.

"Yes, I took it out to see how long it took me to make a box cover,
and then Tom asked me to nail up that box containing the motor
parts, and I laid my watch right down on top, and put the boards
over it."

"Well, the only thing to do is to take off the cover," remarked Tom
grimly.

"Bless my chronometer! That will delay things," said the odd man
with a sigh. "But I suppose there is no hope for it," and he
proceeded to open the box, while Tom, Ned, the circus man and
Eradicate busied themselves over the hundred and one things to be
done before they would be ready for the trip to the interior of
South America.

"Look out, Ned!" called Tom. "You're making those top boards too
long. They'll stick out over the edge, and be ripped off if the box
catches on anything."

"Yes, you can't be too careful," cautioned Mr. Preston. "Each box or
package must be the right weight, or the porters and mule drivers
won't carry them into the interior. You may have to cross rough
trails, and even ford rivers. And as for bridges! well, the less
said about them the better. You aren't going to have any picnic, and
if you want to back out, Tom Swift, now is the time to say so."

"What! Back out?" cried our hero. "Never! I said I'd go and I'm
going. Ned, pass that brace and bit over, will you. I've got to bore
a hole for these screws."

And so the work went on in the big aeroplane shed, which they had
made their packing headquarters.

The Lark, that small, but strong and speedy aeroplane, had been
safely packed, and most of it had been sent on ahead to New York,
where the travellers were to take the steamer. There remained to be
transported their clothing, weapons and ammunition, and several
bundles and cases of trinkets which would be of more value in
bartering with the natives than money. Tom and Mr. Preston had
selected the things with great care, and at the last moment the
young inventor had packed a box of his own, and said nothing about
it. Included in it were some of his own and his father's inventions,
and had one been given a glance into that same box he would have
wondered at the queer things.

"What in the world are you taking with you, anyhow?" asked Ned, of
his chum, noticing the mysterious box.

"'You'll see, if w