Mercury in the Environment
The metal is widely distributed, mostly in forms and amounts that do no harm. The question is whether its concentration by industrial and biological processes now endangers animals and human beings...
Features
The Detection of Gravitational Waves
The existence of such waves is predicted by the theory of relativity. Experiments designed to detect them have recorded evidence that they are being emitted in bursts from the direction of the galactic center...
The Oldest Fossils
The remains of ancient bacteria and algae, some of them more than three billion years old, have been found in Africa, Australia and Canada. They provide evidence on the earliest stages of evolution...
The Evolution of Quasars
It seems that they were much more plentiful when the universe was young than they are today. Their light takes so long to reach us that we can observe millions of them that have long been extinct...
Cooling Towers
Hot water carrying waste heat from a large industrial installation such as a power plant is often best handled by a tower that breaks the water up, cools it in a cross draft of air and then recirculates it...
The Induction Coil
This antecedent of the modern transformer served for nearly a century as the principal source of high-voltage electric current. It figured prominently in three epochal discoveries
The Fortification Illusions of Migraines
The visual displays that are seen before certain headaches provide information on the arrangement of nerve cells in the visual cortex of the brain. The evidence suggests that the pattern is hexagonal...
The Chemical Languages of Fishes
Many fishes have exquisitely sensitive organs of smell. Experiments with catfishes demonstrate that they use this sense for such social purposes as labeling the winners and losers of hierarchical fights...
Departments
50 and 100 Years Ago: May 1971
Science and the Citizen: May 1971
- Letters
Letters to the Editors, May 1971
- Recommended
Books - May 1971
- Mathematical Recreation
Mathematical Games
- Amateur Scientist
The Amateur Scientist - May 1971
- Departments
The Authors - May 1971
Bibliography - May 1971
