7 books
Rivers and Their Mysteries
Harper's Aircraft Book; Why Aeroplanes Fly, How to Make Models, and All about Aircraft, Little and Big
Cuba Past and Present
Panama, Past and Present
Gasolene Engines; Their Operation, Use and Care; A Comprehensive, Simple and Practical Work Treating of Gasolene Engines for Stationary, Marine or Veh
The Ocean and Its Mysteries
In the Wake of the Buccaneers;