New evidence as to the nature of the incoming cosmic rays, their absorbability in the atmosphere, and the secondary character of the penetrating rays found in such abundance at sea level and below

The intensity of latitude-sensitive cosmic rays as would be measured by an electroscope placed just outside the atmosphere has been calculated. The ionization due to incoming electrons of 10 billion electron volts energy in this same electroscope placed 1/20th of an atmosphere beneath the top is found to be 13 times that outside. Electrons do not become penetrating by virtue of high energies even up to 17 billion electron volts. Neither protons nor other penetrating particles of any sort enter the atmosphere in significant numbers from outside the atmosphere. The observed penetrating particles and all other cosmic-ray effects, latitude-sensitive and non-latitude-sensitive, found in the lower atmosphere are practically all secondary effects—splashes from the absorption of electrons, or photons, or both taking place in the outer layers of the atmosphere.