Scientific American Magazine

Jet aircraft are now routinely landed with the help of instruments when visibility is only half a mile. The traditional goal of fully automatic landings under any conditions, however, is still elusive

Some disease bacteria excrete toxin; others do not excrete it but contain it. These latter substances are called endotoxins. How they act on the body is the subject of much current study

A new technique enables drug-addicted animals to give themselves intravenous injections at will. Now some of the factors affecting the voluntary intake of drugs can be investigated in the laboratory

New studies identify regions in the atmosphere that operate like heat engines and others that operate like refrigerators. The latter move heat uphill and chill regions that otherwise would be warm

New systems for measuring the velocities of energetic neutrons have made it possible to extend the use of these particles as probes for investigating the structure of the atomic nucleus

The ability to remember can be studied experimentally. Such studies point to some misconceptions about how different kinds of material are learned and what circumstances may produce lapses of the memory

This apparent displacement of starlight because of the velocity given an observer by the earth's orbital motion was explained in the 18th century by the English astronomer James Bradley

Certain fibers in the frog's optic nerve respond mainly to blue light. This fact supports the idea that the retina is not a mere photographic plate that transmits a picture to the brain but is an analyzing device