A New Way to Control Rickets
Space as Yet Unfathomed
Better Engines for Navy Planes
Speeding up Railway Freight
Man-Made Oases in American Deserts
As population has increased, so, too, has the demand for water—and the controversies over who owns it
Poland Becomes a Maritime Nation
Has Forest Conservation Created a False Alarm?
American Forests, Washington, D.C.
Modern Coal for Modern Markets
Trademarks in Disguise
How Stable is the Earth's Crust?
From the Archeologist's Note Book, December 1931
Butterfly Faking--a New Industry
Stone Age Man's World-Wide Culture
Index to Volume 145, July-December, 1931
Across the Editor's Desk, December 1931
Back of Frontispiece, December 1931
Where Bacteria Hold the Center of the Stage
Our Point of View, December 1931
New Waterproof Lime, First Translations of Maya Glyphs and more
Radio Tube Suits Settled, "Developing" Cream Advertised as a Body Builder, and more
Books Selected by the Editors, December 1931