FIRST ROUND-WORLD FLIGHT NOT YET MADE!

The world has been thrilled in recent weeks by the exploits of the Graf Zeppelin, as it traversed the dreary wastes of Siberia to Tokio; then crossed the Pacific in the path that appears curved on ordinary maps, but that appears straight on the U.S. Navy map on our cover. For this path is a great circle—the shortest distance between two points on a sphere.

But great as was the achievement of Capt. Hugo Eckener, former psychologist, student of Wilhelm Wundt and newspaperman, it is incorrect to call the voyage of the dirigible a "round-the-world flight."

When the army fliers in 1924 flew "around" the Earth, they first skirted the Pacific, by the Aleutian Islands, then crossed Asia and Europe, went around the northern edge of the Atlantic by way of Greenland, and then back to the United States.

What do we mean when we speak of going "around" a sphere?

To go around a sphere, one must go along a "great circle." This is defined as the intersection with a sphere as a plane passing through its center. If you cut a ball into equal halves and put the halves together, the cut forms a great circle. Any number of smaller circles can be drawn on a sphere, but they do not go "around" it.

The army fliers did not go around the Earth in a great circle. Neither did any of the record-breaking "around-the-world" travelers, from Phineas Fogg up to the present. All have gone around a smaller circle, and the only reason that they may be said to have gone around the Earth at all is the fact that they have gone around the North Pole. But if this is the criterion, then the record for circumnavigating the globe belongs to Commander Byrd and the late Floyd Bennett. They went around the pole in a few hours.

CRYSTAL MAY MAKE MORE ACCURATE CLOCKS

A crystal of quartz, similar to those used in radio stations to keep the wavelength constant, may make possible a new era of accurate clock making. Experiments at the Bell Telephone Laboratories by Dr. W.A. Marrison have shown that such a crystal may be made to perform the work of a clock pendulum. Already he has constructed a timepiece that compares in accuracy with the very best of observatory clocks until a few years ago. Since a pendulum is not required, the crystal clock does not require the firm pier on which observatory clocks must be mounted. The crystal clock could be used in a tall office building, on shipboard, or even in aircraft if needed.

REFLEXES, HORMONES, AND ENZYMES

Conditioned reflexes, the building blocks that our behavior is made out of, occupied a prominent place on the program of the Thirteenth International Physiological Congress, held in Boston recently. The famous Russian professor Ivan Petrovich Pavlov, founder of the theory and despite his 80 years still its most vigorous exponent, led the discussion with an account of his most recent investigations.

The simplest act in response to a stimulus is a reflex. For example, your mouth "waters" when you put food into it. That is a simple reflex. A reflex becomes "conditioned" when it has been trained to take place in response to some other stimulus. If our mouth waters when you see or smell food, or even when the dinner bell rings, that is a conditioned reflex. Most of our simpler acts, at least, are conditioned reflexes.

A conditioned reflex is "inhibited" when something about its stimulus fails to fit into the accustomed action pattern. If the bell rings at the wrong time, or if the wrong bell rings at the right time, a sort of censor, acting in or through the higher nerve centers at the top of the brain, signals "nothing doing" and the reflex act is not completed. These inhibitions save much wear and tear that would otherwise be incurred through acting on wrong stimuli.

When the upper brain levels are overstimulated, or rendered oversensitive to ordinary stimuli by drugs such as caffeine, inhibition is interfered with. But if a "quieting" drug, such as a bromide, is administered, inhibition is markedly increased.

Professor Pavlov’s fundamental work has been accepted by a great body of physiologists, but there are disagreements over some matters of detail. For instance, he holds that when an inhibition becomes very powerful, its effect spreads through the brain and causes sleep. But Dr. Nathaniel Kleitman of the University of Chicago cited experiments indicative, in his opinion, that the sleep comes first and puts a stop to the inhibitory process. Drs. H.S. Liddell, O.D. Anderson, and W.T. James of Cornell University also reported experiments not in full agreement with Professor Pavlov’s theory of sleep.