1. S. N. Vernov, G. V. Kulikov, Z. S. Strugalski andG. B. Kristiansen:JETP (engl. ed.),37, 848 (9960).
2. S. Higashi, T. Oshio, H. Shibata, K. Wakanabe andY. Watase:Nuovo Cimento,5, 597 (1957).
3. Note added in proof. —W. F. Baker, R. L. Cool, E. W. Jenkins, T. F. Kycia, S. J. Lindenbaum, W. A. Love, D. Lüers, J. A. Niederer, S. Ozaki, A. L. Read, J. J. Russel andL. C. L. Yuan:Phys. Rev. Lett.,7, 101 (1961).
4. Note added in proof. — In this and the following section we discuss some measurable effects which result from the production of high energy hyperons in the atmosphere. Some of these effects, namely those which do not depend on the comparatively long lifetime of hyperons nor on the negative charge excess among the decay pions can equally well be produced by nucleons in excited states. So far nothing is known about the frequency of occurrence of nuclear isobars at high energy. It is possible that they also play an important role in the nuclear cascade but we shall not consider them here. We are graterful to Dr.V. I. Zatsepin for pointing out their possible importance.
5. The term « nuclear cascade » is not meant to convey the concept of multiplication characteristic of the photon-electron cascade. The production of secondary nucleons seems to play only a minor role. In the main, apparently, a baryon proceeds through the atmosphere in a series of « pionizing » collisions (a term introduced byG. Cocconi) interspersed by decays whenever it suffers a change in its strangeness number.