A Low Water Detector

Notes on Military and Naval Affairs

Surface Condensers for Steam Engines

The Chemistry of Coal

The Plan of Creation

History of the Heliographic Art in Europe and America

Trittin's Coal Oil Lamp

Renewed Activity Among Inventors

Steam Rams

Strong Cannon--American Built-Up Guns

What Can Be Done for Inventors--Advice Gratis and Advice for Pay

The Petroleum Region--The Rock Oil Business--The Extent and Sources of Supply

The New Tariff--Development of Our Iron Interest--A Field for Inventors

Patent Claims

Issued from the United States Patent Office

Recent American Inventions

To Our Readers

The Mortar Fleet and Mortars