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The Dimensions of World Poverty

Two-thirds of the people in the world live in countries whose annual income per capita is less than $300. The pressing problem is hunger, and under present plans it will remain critical for at least 20 years...

By David Simpson

Strong and Ductile Steels

Traditionally the price paid for strength in steel alloys was brittleness. Deeper knowledge of the behavior of solids has led to a class of alloys much tougher than any previously known

By Earl R. Parker and Victor F. Zackay

The Prevention of "Rhesus" Babies

The problem of Rh incompatibility can now be solved by giving an Rh-negative mother an anti-Rh antibody that inactivates any Rh-positive fetal blood cells that may pass into her circulation...

By C. A. Clarke

Visual Illusions

Why do simple figures sometimes appear distorted or ambiguous? Perhaps because the visual system has to make sense of a world in which everyday objects are normally distorted by perspective...

By Richard L. Gregory

Artificial Plasma Clouds in Space

In which clouds of barium atoms are released by rockets at high altitudes and ionized by solar radiation. These clouds of plasma then interact with electric and magnetic fields around the earth...

By Gerhard Haerendel and Reimar Lüst

A Hunters' Village in Neolithic Turkey

Were the inhabitants of Suberde herdsmen or hunters? The analysis of animal bones at the site shows not only that they were hunters but also that they probably "schlepped" meat home in animal skins...

By Dexter Perkins Jr. and Patricia Daly

Transdetermination in Cells

When an embryonic cell begins to differentiate, it is said to be determined for that function. Yet when cells of a fruit-fly larva are transplanted into an adult fly, their determination can change...

By Ernst Hadorn

The Aerodynamics of Boomerangs

A computer-assisted analysis of the forces that affect the flight path of a boomerang, causing it to return to the thrower, is tested by experiments in the field

By Felix Hess


  • 50 and 100 Years Ago: November 1968

  • Science and the Citizen: November 1968

  • Letters

    Letters to the Editors, November 1968

  • Recommended


  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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