Geography of the AirFront matterReading editionChapter navigation2 reading sectionsGo to chapterChoose a chapter…Front matterNATIONAL GEOGRAPHIC MAGAZINE.Beginning of this editionNext chapter →NATIONAL GEOGRAPHIC MAGAZINE.All chapters and sections (2)Opening pagesFront matterOther sectionsNATIONAL GEOGRAPHIC MAGAZINE.VOL. III, PP. 41–52 MAY 1, 1891◇THENATIONAL GEOGRAPHIC MAGAZINE. →