Col. Goethals on the Culebra Slides, State Versus Federal Control of the National Forests and more

New Types for the Japanese Navy, Dussaud's "Cold Light"

Shall We Build Battle Cruisers?

Every Big-gun Cruiser Would Mean One Less Battleship in the Fighting Line

The Enlargement of the Aswan Dam

By the English Correspondent of the Scientific American

The Altamira Wall Paintings

Some Remarkable Specimens of Primitive Man's Art

Sharpening Edge Tools

Cutting Keyways With a Lathe, Making a Socket Wrench

Chair Making One Hundred Years Age, Lettering Triangle

Notched Lathe Dog, Straightening a Back Saw

Strap Hinges vs. T-Hinges

Automatic Fog Gun