Features
Will Bombs Dominate?
Aerial Bomber Has Become Super-Type of Long-Range Heavy Artillery, How Bombs Differ in Their Penetrating and Explosive Action
All For One and One For All
Research in Motor Industry, Cooperation and Exchange of Ideas, Findings, Has Resulted In Numerous Significant Developments
What's Inside the Stars?
Most of Our Present Knowledge of the Composition of the Stars Concerns Only their Atmospheres, Now the Analytical Boring Machine Digs Deeper
Is Light Slowing Down?
Some Physicists Suspect that Changes Occur in the Velocity of Light, Difficult to Prove, On the Whole, the Question Remains Wide Open
Ships Can Carry Autogiros to Spot Submarines
Deep Piers Built in Stiff Tides
New Suspension Bridge Near Tacoma, Two Deep-Water Piers, Enormous Tidal Current Pressure Forces Unique Anchored Caisson Construction
Answer, Echo, Answer
There are Echoes that Magnify Sound and Others that Change Harsh Discords to Harmony, Echoes that Analyze Sound, Whispering Galleries
Pillar Halos
Departments
50 Years Ago, December 1939
- From the Editor
Our Point of View, December 1939
- Recommended
Our Book Corner, December 1939
- Departments
Personalities in Industry, December 1939
Bike Tires Tested, Perfected Rubber Lung, and more
Your Firearms
Camera Angles, December 1939
Camera Angles Round Table, December 1939
Telescoptics, December 1939
Current Bulletin Briefs, December 1939
Legal High-Lights, December 1939
Index To Volume 161, July-December, 1939