https://archive.org/details/hiddenpeoplestor00mill
The hidden people : the story of a search for Incan treasure
by Miller, Leo Edward, 1887-; Bransom, Paul, 1885-
https://archive.org/details/intigerslair00mill
In the tiger's lair
by Miller, Leo E. (Leo Edward), 1887-
The hidden people is a story of adventure. It relates the experiences of two Americans who go in search of – and locate – the lost treasure of the Incas. in the tiger's lair is the sequel.
The Hidden People and In the Tiger's Lair by Miller
Carolin