
Daylight Projection of Opaque Subjects

Daylight Projection of Opaque Subjects

Is the Practical Helicopter in Sight?, Measuring Vapor Pressures and more

The Army School for Weather Observers

The World War on Rats

The Motor Sled Versus the Dog Sled

X-Ray Tubes by the Hundreds
How the Trained Mechanic and the Skilled Glassblower Have Been Replaced by Automatic Machinery

When a Lighting Fixture is not a Fixture, What is Dry Rot?

Tuning and Testing
How the American Automobile Engine is Limbered Up and Tested for Flaws

A New Magnesium Alloy for Motor Pistons

Piloting the Ship with the Ears, Rust Preventives

Handling High Voltage with Bare Hands

New York's Radio Pilot Cable, To Preserve a Beautiful and Historic Work and more

The Romance of Tungsten
How This Erstwhile Brittle Metal Was Made Available for Lamps

Mining Coal with a Dredge

Air Bags for the Airplane that Lands on Water

A Man-Sized Helicopter that Leaves the Ground with Full Load

The X-Ray in the Shop

Putting Infra-Red Rays to Work
How the French Army and Navy Make Use of Heat Rays for Invisible Signalling

What About Our Commercial Aviation?