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Scientific American Magazine Vol 219 Issue 5

Scientific American Magazine

Volume 219, Issue 5

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Features

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

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

Earl R. Parker, 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

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

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

Gerhard Haerendel, 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

Dexter Perkins Jr., 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

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

Felix Hess

Departments

Letters to the Editors, November 1968

50 and 100 Years Ago: November 1968

The Authors

Science and the Citizen: November 1968

Mathematical Games

The Amateur Scientist

Books

Bibliography