Gravitation—I
And the Principle of Relativity
Features
Bird Life of a Big City
Effect and Kind of Rust
Remarkable Progress in War Surgery
A Prehistoric Pueblo Indian Ruin
Explored and Restored by the American Museum of Natural History
Animal Camouflage
The Golden Apple
How to Economize Coal
Exhaust Valve Troubles
A Report on an Important Aeronautical Problem
War Bread
Oil Seeds and Vegetable Oils
Soy Beans make Valuable Food
Women in British Munitions Factories
Work Behind the Lines as Important as Service at the Front
Safety First for Foundrymen
Daylight Seeing
Stammering, and the Ladies
The Relation of Locomotive Maintenance to Fuel Economy
Drilling Gas and Oil Wells
Meteorology and Aeronautics
The Relation of Topographic and Climatic Factors
The Chemistry of Silicates
With Reference to their Use in Dental Operations