Multiple Scattering of Fast Electrons and Alpha-Particles, and Curvature of Cloud Tracks Due to Scattering

about the zenith with intensity prominences in the zenith-angle range from 5' to 10', near 20', and in the range from 35' to 40'. These. results tend to confirm the predictions of Schremp relative to the existence of a fine structure due to a line or banded nature of the energy spectrum forcosmic rays at infinity. That the finestructure may not arise partly from magnetic effects is not entirely precluded, as the penumbral bands of the Lemaitre-Vallarta theory form a sort of "C"and might give rise to a perturbation of the fine structure due to absorption without entirely destroying the approximate symmetry of the pattern. But as Columbia, Missouri is near the "knee" of the geomagnetic latitude, intensity curve and the pattern shows an approximate symmetry about the zenith, the most plausible explanation in terms of primary cosmic rays seems to be that there are lines or bands in the energy spectrum at infinity. Then, it is necessary that these lines or bands be successively absorbed out by range absorption by increasing the atmospheric path traversed by the primary radiation. This explanation of the fine structure in terms of absorptive effects is not in discord with the present results, Ribner's results, and the deductions from Johnson's data. Absorption experiments are in progress to test this interpretation of the experimental results. The author wishes to express his deepest appreciation to Professor N. S. Gingrich whose keen advice, earnest cooperation, and inspiring stimulation were invaluable throughout the course of this investigation. He also wishes to express his gratitude to Professor E. J. Schremp for many invaluable suggestions and constructive criticisms.