From the July 25, 1931, issue


A good place for a photographer to take a picture, this penstock will be serving an even better purpose when it begins to carry water through the dam to turn the huge turbines of the Ruskin power plant, British Columbia.

The flow of water through this 19-foot-diameter intake pipe is controlled by the butterfly valve just behind the workman in the photograph. The entire valve weighs 98 tons and its moving disk, 47 tons. It is operated hydraulically by a rubber tube carrying water under pressure.


The largest part of the universe is forever out of our reach. This is the opinion of the Abbé G. Lemaitre, famous Belgian astronomer, whose ideas of an expanding universe have been one of the recent sensations of astronomy.

In a report to the Royal Astronomical Society, of London, his first paper on the subject to be published in English, he makes this statement, which indicates that even if telescopes are made many times larger than any in existence or projected at present, they would not see beyond a definite limit, even though there might be plenty of stars and nebulae beyond.

Our present-day telescopes are not very far from this limit. The 100-inch reflector at Mt. Wilson, largest in the world, can detect objects as far away as 50,000,000 parsecs, the parsec being the astronomers unit of distance and equal to 18 million million miles. About 17 times this distance is the limit beyond which we cannot see, according to the Abbé.

The reason for the invisibility of very distant objects is that all their visible light is increased to wavelengths so great that they cannot be detected. This shift in the wavelength of light as it is moving toward or away from Earth is well marked for the nearer objects, and is called the Doppler effect. The eye, and the photographic plate, are sensitive only to a limited band of wavelengths.


Solid matter was actually solid–until about 100 years ago. Then it was decided that most of a solid is empty space with solid atoms scattered about like bees in a swarm.

Now the bees may not even be solid.

Latest news from the atomic research front shows that even the atom has lost its solidity. At the Bartol Research Foundation at Swarthmore, Pa., a stream of atoms has been made to behave like immaterial waves scattered in many directions.

Dr. Thomas H. Johnson of the Franklin Institute, Philadelphia, has fired a stream of hydrogen atoms at the surface of a crystal of lithium fluoride and by observing the spread of the reflected atoms, has found the wavelength of the atoms and has learned how the network of atoms on the crystal surface is fitted together.

From the Nature Index

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