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In Science this month Professor Einstein published a brief communication entitled "Lens-like Action of a Star by the Deviation of Light in the Gravitational Field." It appeared that a Bohemian-born dishwasher named Rudi Mandl had come to him with an idea which he wanted the good grey sage of Princeton to formulate in mathematical terms. The idea: that in a certain very special circumstance the space-curvature around a star would act like an optical lens on the light from an-other star. Einstein showed that if an observer viewed two stars, one much farther away than the other but both in the same line of sight, the bending of light around the near star should make the far star appear as a luminous ring. Actually no telescope now in use would be powerful enough to bring out this halo, and the phenomenon, if ever observed at all, would appear simply as an increase in brightness of the far star.
In his communication Dr. Einstein, whose mathematics is better than his English, spelled the word luminous, "luminius."
* Small particles like dust, fortuitous aggregations of molecules and droplets of water tend to deflect short wave lengths of light which approximately "fit" them, while longer wave lengths curl around these small obstacles. Long infra-red rays go farther through fog than visible light and still longer radio waves can go through buildings. In the visible spectrum, blue light is shorter in wave length than red. In the case of the evening sun, the blue components are scattered in all directions, and this subtraction makes the sun look red. But the blue light is scattered again & again in the atmosphere so that some of it returns to the eye of the observer, and he therefore sees a blue sky.