In Touch with the Conditions

A New Theory of Gun Erosion

Electrolysis in Armored Concrete

The Value of the Nile Barrages to Egypt

By the English Correspondent of the Scientific American

Seal Hunting on the Ice Floes of the North

The North Carolina-Virginia Inland Waterway

Branch Railways by the Telpherage System

The Carnegie Technical Schools, Pittsburg, Pa

Capt. Ferber's Aeroplane Experiments

By the Paris Correspondent of the Scientific American

Adjustable Boring Tool

Armored-Concrete Railway Tie

Lubricator for Street Railway Motors

Stanchion for Cattle

Screw Driver with a Centering Device

Recording Auto Speed Meter