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Features

The Mohole

The U. S. may drill a hole to the Mohorovicic discontinuity between the earth's crust and the underlying mantle. The hole would provide priceless evidence on the earth's history and internal constitution

By Willard Bascom

Family Planning in the U.S.

Where the birth rate of the U. S. was once fairly stable, practices of contraception have now made it a variable. How these practices affect population trends has been examined by a large-scale study

By Ronald F. Freedman, Pascal K. Whelpton and Arthur A. Campbell

Germination

Many plants have evolved natural mechanisms that keep their seeds "dormant" until the optimal time for sprouting. These mechanisms include chemical responses to light and rainfall

By Dov Koller

The Solar System beyond Neptune

Pluto, our sun's most remote and mysterious planet, may once a satellite of Neptune. Current theories about its origin provide new clues to the genesis of the solar system

By Owen Gingerich

How Reptiles Regulate their Body Temperature

Although they lack internal controls, they can maintain a high temperature by their behavior. A lizard, for example, can raise its temperature by changing the position of its body in the sun

By Charles M. Bogert

Aligned Crystals In Metals

Crystals have different properties in different directions. Alignment of the crystal grains within a piece of metal can significantly alter its mechanical and magnetic behavior

By B. D. Cullity

The Sex Gas of Hydra

Usually this small animal reproduces by budding, but it can also develop male and female organs for sexual reproduction. What factors determine which method of reproduction it uses?

By W. F. Loomis

Departments

  • 50 And 100 Years Ago: April 1959

  • Visual Perception and Personality

  • Science And The Citizen: April 1959

  • Letters

    Letters to the Editors, April 1959

  • Errata

  • Recommended

    Books

  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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