A Factory in the Wilderness
With Bandits and Savages for Workmen, a Huge Quebracho Extract Plant Was Built in the Heart of the Jungles of Paraguay
Volume 140, Issue 4
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Features
Our Light-Plane Contest
Complete Details of the Scientific American 500 Dollar Prize for a Light Airplane Design
Solar Research for Amateurs--I
By Means of the Newly Developed Spectrohelioscope, Vivid Phenomena on the Sun May Now Be Observed in Motion by the Amateur Scientist
From the Scrap-book of Science, April 1929
A Mountainous Earthen Dam
Gigantic Earth-fill Dam In South Carolina, One of the Largest In the World, Will Be a Part of Huge Hydro-electric Project
Exploring the Biblical Beth-shan
For Thousands of Years, Invading Armies Stormed This Little Hill at the Crossroads of Palestine
Boston's New "Madison Square Garden"
How a Railway Station and an Auditorium Were Combined to Double the Use of Land
Quantitative Analysis of the Sun
The Ordinary Identification of the Chemical Elements on the Sun by Means of the Spectroscope Has Long Been Possible. The Newest Development Is Quantitative Analysis of These Same Elements
Animal Allies of the Physician
How Vaccines, Snake Bite Serums, and Antitoxins Widely Used by Doctors are Prepared in a Modern Serum Laboratory
How People Differ Mentally
A Large Part of the Commonest Beliefs About Our Individual Powers and Limitations Are Not True
New Uses for Coal and Wood
Scientists, Seeking New Industrial Uses for Wasted Raw Materials, Produce Gasoline from Coal and Seek to Make Food from Wood Pulp
The Month in Medical Science, April 1929
A Review and Commentary on Progress in the Medical and Surgical Fields
Why Do Insects Migrate?
More Controversy Than Knowledge Surrounds Their Mysterious Flights From North to South and Return
Safety for Those Who Go Down to the Sea in Ships
Paper Milk Bottles
An Improvement in Milk Distribution Which May Revolutionize a Vast Industry
Making the Farm Pay
A Practical Farmer Gives, From His Experience, Some Rules For Running a Farm Scientifically
Ultra-Violet Transmitting Glass--Has it Made Good?
Observations on the Physics and Physiology of Special Window Glass for Transmitting Indoors Part of the Vital Ultra-Violet Rays of the Sun, Based on the Opinions of Foremost Scientific Authorities