Columbia subject headings:
Clarke, Thurston.
Tropics--Description and travel.
Voyages around the world.
Harvard subject headings:
Clarke, Thurston.
Equator--Description and travel.
Tropics--Description and travel.
Voyages around the world.
Princeton subject headings:
Clarke, Thurston.
Tropics--Description and travel.
Voyages around the world--1951-.