Volume 210, Issue 4
You are currently logged out. Please log in to download the issue PDF.
Features
Chromosome Puffs
These enlarged regions on the giant chromosomes found in some insect cells have been shown to be active genes. They probably produce the nucleic acid that translates the genetic information
The Chemistry of Concrete
The chemical reactions that occur when water is added to portland cement in the mixing of concrete continue for months. Recent studies have elucidated the process
The Hallucinogenic Drugs
These powerful alkaloids, tools for investigating mental illness and perhaps for treating it, have become the subject of a debate: Do their constructive potentials outweigh their admitted hazards?
A Neolithic City in Turkey
An ancient mound now known as Catal Hüyük has yielded evidence that communities with highly developed economic structure, religion and art existed as long ago as 7000 B.C. and perhaps even earlier
The Interaction of Light with Light
Intense beams of laser light interact with crystals to yield novel optical effects. For example, when two beams meet in a crystal they can add or subtract to produce beams of two new wavelengths
Sound Communication in Honeybees
It has been known for some time that bees perform an intricate dance in directing their hivemates to a source of food. Now it appears that they also transmit information by means of sound
The Petrified Forests of Yellowstone Park
The most extensive fossil forests of their kind in the world, they contain much information about the climate and geologic history of the Rocky Mountain region some 55 million years ago
The Solar Wind
Comet tails and other phenomena indicate that a thin, hot gas of solar particles flows past the earth at supersonic speeds. This gas is simply the expanding corona of the sun
Departments
Departments
The Authors
Bibliography
Letters
Letters to the Editors, April 1964
50 and 100 Years Ago: April 1964
Science and the Citizen: April 1964
Mathematical Recreation
Mathematical Games
Reviews
Books
Amateur Scientist
The Amateur Scientist