《The National Geographic Magazine Vol. 04》 - 免费有声读物

The National Geographic Magazine Volume 4, articles published in 1892 and 1893.
The Evolution of Commerce: Annual Address by the President, Gardiner G. Hubbard
Studies of Muir Glacier, Alaska
Geography of the Air: Annual Report by Vice-President General A. W. Greely
The Mother Maps of the United States
An Expedition through the Yukon District
The North American Deserts
The Alaskan Boundary Survey
Collinson's Arctic Journey

Notes:
Topographic Survey of Canada
Lieutenant Peary's Crossing of northern Greenland
Geographic Prizes