Scientific American Magazine

The input-output tables on the next seven pages divide the economy into 81 sectors and list the transactions among them. The numbers are the constants of the technological relations among the sectors

The cell is a factory and enzymes are its machines. Two feedback systems control production, one regulating synthesis of enzymes, another their activity. Models of the two systems are described

Dilation and constriction of the pupils reflect not only changes in light intensity but also ongoing mental activity. The response is a measure of interest, emotion, thought processes and attitudes

Continuous fields as strong as 250,000 gauss, 500,000 times the strength of the earth's magnetic field, have been generated at the National Magnet Laboratory

Excavations at Nea Nikomedeia in northern Greece have uncovered a community of 8,000 years ago. Its remains suggest that agriculture and animal husbandry came to Europe earlier than has been supposed

Certain moths can hear the ultrasonic cries by which bats locate their prey. The news is sent from ear to central nervous system by only two fibers. These can be tapped and the message decoded

A chunk of rock less than a mile in diameter, Icarus comes closer to the sun and the earth than any other asteroid whose orbit has been accurately computed. It should miss us by four million miles in 1968

In 1816 Robert Stirling invented an engine that operated by heating and cooling air in a closed cycle. The cycle has now been "reversed" in an efficient machine for cooling things to very low temperatures