April 1963

Continental Drift
“In 1912 Alfred Wegener proposed that the continents had originated in the breakup of one supercontinent. His idea has not been widely accepted, but new evidence suggests that the principle is correct. The range of opinion divides most sharply between the position that the earth has been rigid throughout its history, with fixed ocean basins and continents, and the idea that the earth is slightly plastic, with the continents slowly drifting over its surface, fracturing and reuniting and perhaps growing in the process. Whereas the first of these ideas has been more widely accepted, interest in continental drift is currently on the rise.”

Optical Transistor
“Gallium arsenide, the crystal that has recently come into prominence for making the light-amplifying devices called lasers, has now been used to make an optical analogue of the junction transistor, a device for amplifying or switching electric signals. The advantage of the optical transistor is that light can cross the base region much faster than electrons can. To obtain high-speed (or high-frequency) operation in a conventional transistor the base must be made extremely thin to minimize signal travel time, and thinness is difficult and costly to achieve. In the optical transistor extreme thinness is unnecessary.”

April 1913

Preparing for the Post-Fuel Age
“In a few centuries the world's coal mines will be exhausted. Whence shall we derive the energy to turn the wheels of industry? By harnessing nature, is the answer. Long before we took stock of our fuel supply and found that we must husband what little we have left, scientific dreamers wondered whether natural forces could not in some way be utilized. Already we are making extensive use of water power, or ‘white coal’ as it is called. The tide has yielded us some power and so have the waves. It is interesting to see what inventors have been doing toward the engines of the future. This issue's cover [see illustration] is a typical case (now being installed in Venice, Calif.), picked out at random from hundreds of patents.”

Allure of the Foreign
“Hama, the Hamath of the Bible, one of the oldest cities of Syria, is situated in the valley of the Orontes, 110 English miles northeast of Damascus. The Orontes River flows through the City in the form of an S, and upon its banks are four huge water wheels, each bearing a name of its owner. They are used for pumping up the water of the Orontes for irrigation purposes, and also for supplying the town. The largest wheel has a diameter of about 70 feet, and the Syrians declare it is the largest in existence. Like the others, it is built of wood, a dark mahogany. The axle is of iron. The creaking of the wheels is incessant day and night. They never stop.”

For a photo album on the interest in foreign culture in 1913, see www.ScientificAmerican.com/apr2013/foreign-culture

April 1863

A Prairie's Value
“It is a singular fact that what were vast treeless prairies in Illinois, twelve years ago, are now covered with a dense growth of thrifty young forest trees, comprising various species of oak, hickory, cottonwood, ash, etc. So rapid has been this change in many localities, that where some of the early settlers located, twenty to twenty-five years ago, without a tree around them, they can now cut and hew good building timber a foot square. Prairie land, when kept from the annual fall burning formerly practiced by the Indians, rapidly produces a growth of trees. Some of the old citizens, who greedily located the timber land when they came to this country, and were careless about acquiring prairie, now find the latter of more value than the former; their timber has grown faster than they used it.”

Japanese Paper
“Dr. McGowan, in a recent lecture on Japanese customs, exhibited an overcoat made of paper, perfectly strong and serviceable. In this country we have paper collars, but in Japan they go further and have paper handkerchiefs, which are very soft and of very fine texture. But the Japanese are more delicate than we in one respect; after they have used a handkerchief they throw it away, and are thus saved the trouble of washer women.”