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Electrical Propulsion in Space

Economy of propellant is the chief advantage of electrical rocket engines now being developed. Their low thrust will limit their use to vehicles previously boosted into an orbit by other means

By Gabriel Giannini

New Penicillins

By altering the groups of atoms that are attached to the core of the penicillin molecule, chemists have produced penicillins that are effective against resistant strains of microorganisms

By Anthony H. Rose

Pre-Cambrian Animals

Until recently the fossils of organisms that lived earlier than the Cambrian period of 500 to 600 million years ago were rare. Now a wealth of such fossils has been found in South Australia

By Martin F. Glaessner

Gravity

Albert Einstein showed that gravitation can be interpreted as a geometrical property of space-time. His further hope, of relating gravity and electromagnetism, is still unfulfilled

By George Gamow

How Themistocles Planned the Battle of Salamis

A newly discovered tablet is the great general's decree on the eve of the battle. It reveals that he called for an orderly evacuation of Athens and deliberately chose to meet the Persians in a strait

By Michael H. Jameson

Lee Waves in the Atmosphere

Formed downwind from hills and mountains, the waves create many strange and beautiful cloud types. Meteorologists neglected lee waves until sailplane pilots began exploiting them to reach great altitudes

By R. S. Scorer

Shadows and Depth Perception

The ability to see that a surface curves toward or away from us depends upon how light and shadow are distributed. Investigators have undertaken to determine if the ability is innate or learned

By Eckhard H. Hess

Monomolecular Films

Many physical, chemical and biological processes involve thin films of material at surfaces. In these processes the most important role is played by a film just one molecule thick

By Herman E. Ries

Departments

  • 50 and 100 Years Ago: March 1961

  • Science and the Citizen: March 1961

  • Letters

    Letters to the Editors, March 1961

  • Recommended

    Books

  • Mathematical Recreation

    Mathematical Games

  • Amateur Scientist

    The Amateur Scientist

  • Departments

    The Authors

  • Bibliography

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March 1961

See the World from a Different Perspective

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