In attempting to find a seasonal or winter-summer difference between the integrated value of the cosmic-ray ionization from sea level up to the top of the atmosphere at Omaha we obtain much too large a difference to be interpreted as an "atmospheric-temperature," or seasonal effect, at all. By comparison with Forbush's world-wide cosmic-ray changes we find in our results new evidence for a change with time in the total energy brought into the earth by cosmic rays.

• Received 17 July 1939

DOI:https://doi.org/10.1103/PhysRev.56.491