Columbia subject headings:
Duff (Sailing ship)
Gregory, William, active 1800--Travel.
Missions.
South America--Description and travel--Early works to 1800.
Voyages and travels.
Harvard subject headings:
Duff (Sailing ship)
Gregory, William, active 1800--Journeys.
Missionaries--Diaries.
Missions
Providence and government of God--Christianity
South America--Description and travel--Early works to 1800
Voyages and travels
Voyages and travels--Religious aspects--Christianity
Princeton subject headings:
Duff (Sailing ship)
Gregory, William, active 1800--Travel.
Missions.
South America--Description and travel--Early works to 1800.
Voyages and travels.