"But why should there be giants there any more than anywhere else?"
asked Ned.

"No particular reason," answered his chum. "But, according to the
last word Mr. Preston had from his agent, that was where he was
heading for, and that's where Zacatas, his native helper, said he
lost track of his master. I have a theory that the giants, if we
find any, will turn out to be a branch of a Patagonian tribe."

"Patagonians!" exclaimed Ned.

"Yes. You know the natives of the Southern part of Argentina grow to
a considerable size. Now Patagonia is a comparatively bleak and cold
country. What would prevent some of that big tribe centuries ago,
from having migrated to a warmer country, where life was more
favorable? After several generations they may have grown to be
giants."

"Bravo!" exclaimed Mr. Damon. "It's a good theory, at any rate, Tom.
Though whether you can ever prove it is a question."

"Yes, and a big one," agreed the young inventor with a laugh.

For some days they traveled along over a comparatively flat country,
bordering the river. At times they would pass through small native
villages, where they would be able to get fresh meat, poultry and
other things that varied their bill of fare. Again there would be
long, lonely stretches of forest or jungle, through which it was
difficult to make their way. And, occasionally they would come to
fair-sized towns where their stay was made pleasant.