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The Modulation of Laser Light

The great potential of the laser for use in long-distance communication systems has been brought closer to realization by the development of large-bandwidth, low-power modulators

By Donald F. Nelson

A Stone Age Campsite at the Gateway to America

Onion Portage in Alaska is an unusual Arctic archaeological site. It provides a record of human habitation going back at least 8,500 years, when its occupants were not far removed from their forebears in Asia...

By Douglas D. Anderson

Stars in Contact

About one star in 1,000 is in actuality a pair of stars so close together that their atmospheres exchange material. These contact binaries have something to tell us about the evolution of stars...

By O. J. Eggen

Standards of Measurement

The goal is to define standards of length, mass, time and temperature that are both precise and reproducible. Of the four only mass still lacks a referent in nature

By Allen V. Astin

The Brain of Birds

Since birds have a smaller cerebral cortex than mammals, are they less intelligent than mammals? Recent work suggests that they may simply use other parts of the brain to effect intelligent behavior...

By Kenneth A. Matyniak and Laurence Jay Stettner

The Discovery of DNA

In 1869 Friedrich Miescher found a substance in white blood cells that he called "nuclein." Cell biologists saw that it was a constituent of chromosomes and hence must play a major role in heredity...

By Alfred E. Mirsky


Is polishing simply fine-scale abrasion or is it more akin to melting? Recent findings suggest that neither of these two old rival hypotheses is entirely correct

By Ernest Rabinowicz

Plants without Cellulose

It was once believed that cellulose was the structural material in the cell walls of all green plants. Now it appears that other substances are employed for this purpose in certain marine algae...

By R. D. Preston


  • 50 and 100 Years Ago: June 1968

  • Science and the Citizen: June 1968

  • Letters

    Letters to the Editors, June 1968

  • Recommended


  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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