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Features

Conversion to the Metric System

Great Britain, which developed the imperial system of weights and measures, is now well into a period of transition to the metric system. Before long the U.S. will be the only major nonmetric nation

By Lord Ritchie-Calder

Globular-Cluster Stars

Within our galaxy are some 200 globular clusters, each consisting of 100,000 to a million stars. The study of models indicates they began life 10 to 15 billion years ago when the universe was young

By Icko Iben

The Multiple Sclerosis Problem

The cause of this disease of the central nervous system is unknown. The variations in its incidence around the world, however, suggest that it results from infection by a virus with a long latent period

By Geoffrey Dean

Negative Viscosity

In most fluid systems differences in velocity are obliterated by positive viscosity. In some rotating systems, however, nonuniform flows can be maintained by negative viscous effects due to eddies

By Norman E. Gaut and Victor P. Starr

The Love Song of the Fruit Fly

Most species of Drosophila have overlapping ranges, yet hybrid fruit flies are rare. One reason is that in courtship the females respond to a unique signal that is emitted only by males of the same species

By A. W. Ewing and H. C. Bennet-Clark

Network Analysis

This new planning method can be applied to power grids, computer networks, gas pipelines and other flow-handling systems in order to increase their effectiveness and reliability and reduce costs

By Howard Frank and Ivan T. Frisch

Population Trends in an Indian Village

Population growth is beginning to slow down in villages of the Punjab. The analysis of such variables in the process as education, health care and economic status may influence India's family-planning program

By Carl E. Taylor

Departments

  • 50 and 100 Years Ago: July 1970

  • Science and the Citizen: July 1970

  • Nerve Cells and Behavior

  • Letters

    Letters to the Editors, July 1970

  • Recommended

    Books - July 1970

  • Mathematical Recreation

    Mathematical Games - July 1970

  • Amateur Scientist

    The Amateur Scientist - July 1970

  • Departments

    The Authors - July 1970

  • Bibliography - July 1970

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July 1970

Think Outside the Gift Box