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Balloon Mines to Put the Air Out of Action

Will Bombs Dominate?

Aerial Bomber Has Become Super-Type of Long-Range Heavy Artillery, How Bombs Differ in Their Penetrating and Explosive Action

By Arthur E. Oxley

All For One and One For All

Research in Motor Industry, Cooperation and Exchange of Ideas, Findings, Has Resulted In Numerous Significant Developments

By J. J. Frey

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

By Henry Norris Russell

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

By Douglas W. F. Mayer

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

By Charles F. A. Mann

Answer, Echo, Answer

There are Echoes that Magnify Sound and Others that Change Harsh Discords to Harmony, Echoes that Analyze Sound, Whispering Galleries

By Albert Carr

Pillar Halos


  • 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

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