Last week in Paris Dr. Robert Andrews Millikan reiterated in a paper read before the International Electrical Congress his belief that cosmic rays are the "birth cries" of atoms newly born in the cold spaces between the stars. His paper was written before he heard of a report published last week in the Physical Review by his fellow Nobel Prizewinner, Dr. Arthur Holly Compton, now in Peru. Old is the quarrel between Dr. Millikan and Sir James Hopwood Jeans, who calls cosmic rays the "death wails" of matter on the stars. Dr. Millikan's friend Dr. Compton last week attacked his cosmic ray theories from a new quarter.
What is known is that cosmic rays exist. They are infinitesimal, strike Earth with over 50,000,000 volts of power. What is not known is where they come from and why. Jeans locates their source on the stars, Millikan between the stars. They may be photons, the ultimate unit of light radiations. Photons could not be deflected by Earth's magnetic field. Or cosmic rays may be electrons, electrically charged matter which would be deflected by Earth's magnetic field. Since Dr. Millikan's researches showed that cosmic rays hit the Earth with the same force at different latitudes, he decided they could not be electrons, must be photons.
In March Dr. Compton, declining a chance to be president of Princeton University, set out with a 250-lb. machine to watch cosmic rays on Pacific mountaintops in Panama, Peru, New Zealand, Hawaii, Alaska. His preliminary report last week flatly contradicted Dr. Millikan's findings. Dr. Compton found "definite differences in the intensity of the cosmic rays at different latitudes, with a minimum at or near the Equator and increasing intensity toward the North and South Poles." These differences made him suspect that cosmic rays were streams of electrons, particles of electrically charged matter. More upsetting to Dr. Millikan's theories of reborn matter was another suspicion: that energized electrons would probably not be foundlings from distant stars or interstellar space, would probably have originated in the Earth's atmosphere.
Observers last week were already writing Dr. Millikan's answer for him. In his laboratory Millikan had seen cosmic rays penetrate 50 ft. of lead, knock electrons out of atmosphere atoms. Such electrons, Dr. Millikan might say, would naturally spiral toward the poles, knocked out of Earth-atmosphere atoms by cosmic rays still unexplained by Dr. Compton.