National Geographic May 1919

The Industrial Titan of America: Pennsylvania, Once the Keystone of the Original Thirteen, Now the Keystone of Forty- eight Sovereign States
Blessed with vast natural resources, immense industry, and the unconquerable spirit of progress, the state of Pennsylvania offers a glimpse of America’s majestic future.
Helium, the New Balloon Gas
The world’s only workable supply of helium promises to make balloons and airships a safe and practical reality.
Hunting Big Game of Other Days: A Boating Expedition in Search of Fossils in Alberta, Canada
Thanks to a once warmer climate, the prairies and forests of Alberta yield fertile prospecting for dinosaur remains.
Indiana’s Unrivaled Sand- Dunes- -A National Park Opportunity
Abundant precipitation and a reliable source of fresh water make the dunes along a 20- mile stretch of Lake Michigan a habitat for a unique variety of flora.