Scientific American Magazine Vol 223 Issue 5

Scientific American Magazine

Volume 223, Issue 5

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Features

Fast Breeder Reactors

Nuclear reactors that use fast neutrons to produce more fuel than they consume are a promising approach to producing electric power with a minimum of strain on energy resources and the environment

Glenn T. Seaborg, Justin L. Bloom

The Genetic Activity of Mitochondria and Chloroplasts

These organelles of cells contain DNA, RNA and their own apparatus for synthesizing proteins. Their resemblance to bacteria suggests that they may be descended from free-living bacteria-like organisms

Ursula W. Goodenough, R. P. Levine

Woodhenges

The celebrated Stonehenge is only one of 80 henge monuments known in Britain. Recent excavations at two of the largest henges show that they enclosed structures that were made not of stone but of wood

Geoffrey Wainwright

Superdense Water

One of the codiscoverers of this remarkable substance takes up the question of whether it represents a new, polymeric form of water or is merely ordinary water with impurities

Boris V. Derjaguin

Automatic Analysis of Blood Cells

Microscopic examination of white cells is laborious and expensive. An experimental computer-operated system has been developed that identifies and counts cell types and describes cells quantitatively

Marylou Ingram, Kendall Preston Jr.

The Great Albatrosses

The royal albatross and the wandering albatross are the largest birds in terms of wingspan. The species are so much alike that they probably evolved from a common ancestor in the recent past

W. L. N. Tickell

Experiments in Intergroup Discrimination

Can discrimination be traced to some such origin as social conflict or a history of hostility? Not necessarily. Apparently the mere fact of division into groups is enough to trigger discriminatory behavior

Henri Tajfel

Why the Sea is Salt

The sea contains more than 70 elements in addition to sodium and chlorine. The global cycles that remove and replenish them involve rainfall, volcanoes and the spreading of the ocean floor

Ferren Maclntyre

Departments

Letters to the Editors, November 1970

50 and 100 Years Ago: November 1970

The Authors

Science and the Citizen: November 1970

Mathematical Games

The Amateur Scientist

Books

Bibliography