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General Theory of Relativity. If a man and an egg drop from an airplane at the same moment they will strike the earth, if there is no air resistance, at exactly the same moment. Such is an effect of gravity. Isaac Newton described the effect well with his laws of gravity. Albert Einstein did better with his general theory of relativity. He found a metric (a measure) with which he could subdivide practically everything that happened in his fourth dimensional world. It was a theoretical measuring unit invented by Georg F. B. Riemann (1826-66), mathematician.
The Riemann metric subdivides time, space, undulations, tensions and the other simplest phenomena of the world. By multiplying that unit as though it were (crudely) pounds, gives the force of gravity between, say, the earth and the man or egg falling from the airplane. Gravity is thus not unique as Newton believed. It is a part of the world's pervasive unity. Again Dr. Einstein's suspicion brought him to perception. This was in 1916.
Coherent Field Theory. The natural phenomenon for which the general theory of relativity did not account was electromagnetism. Dr. Einstein in 1905 had shown that electricity and magnetism were different aspects of one world activity. In 1919 he showed that gravity was another world activity. It was impossible, he believed, that gravity and electro-magnetism were two distinct world activities. His Riemann metric must be inaccurate.
So he was obliged to re-examine his whole world and to remeasure it. Euclidean methods of measurements were only approximate. So, too, were Riemannian.
Working in his Berlin study, musing in his sailboat on Wannsee, lolling in his beach chair at Luebeck, Albert Einstein figured out a new metric. It lies between Euclid's and Riemann's conceptions. It shows that gravity, electricity, magnetism. everything is a logical, not chance, part of the world. It enabled him last week to phrase in mathematical terms a theory by which "everything in the world" can be explained.
Consequences. Albert Einstein's theories have altered human existence not at all. But they have revolutionized human understanding of existence.
One human field where the theories may have consequences is in aviation. The airplane motor is operated by electricity set moving by the magneto and intensified by electro-magnetic coils. When the plane is on the ground electricity and its spark act in a definite fashion. Perhaps that fashion changes when the plane is high in the air—powerfully lifted against the earth's force of gravity and swiftly moved with or against earth's rotational force. The possibility of such change may account for some airplane accidents. Perhaps such possible changes can be foreseen, calculated, forestalled. Perhaps—not to venture upon any more specific perhapses-—he pull of the Einstein intellect will raise mankind yet higher by the bootstraps.